Electricity in Locomotion - An Account of its Mechanism, its Achievements, and its Prospects

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Title: Electricity in Locomotion - An Account of its Mechanism, its Achievements, and its Prospects
Author: Whyte, Adam Gowens
Language: English
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The Cambridge Manuals of Science and
Literature

ELECTRICITY IN LOCOMOTION

CAMBRIDGE UNIVERSITY PRESS
London: FETTER LANE, E.C.
C. F. CLAY, MANAGER

[Illustration]

Edinburgh: 100, PRINCES STREET
London: H. K. LEWIS, 136, GOWER STREET, W.C.
Berlin: A. ASHER AND CO.
Leipzig: F. A. BROCKHAUS
New York: G. P. PUTNAM'S SONS
Bombay and Calcutta: MACMILLAN AND CO., LTD.

_All rights reserved_

ELECTRICITY IN
LOCOMOTION

AN ACCOUNT OF
ITS MECHANISM,
ITS ACHIEVEMENTS, AND
ITS PROSPECTS

ADAM GOWANS WHYTE, B.Sc.

Editor of _Electrical Industries_
and _Electrics_

Cambridge:
at the University Press
1911

TO
EMILE GARCKE

_With the exception of the coat of arms at the foot, the design on
the title page is a reproduction of one used by the earliest known
Cambridge printer, John Siberch, 1521._

PREFACE

In the following pages an attempt is made to give a clear picture of
the part which electricity has taken and will continue to take in the
development of locomotion.

Some of the aspects of electric traction are highly technical; others
are purely financial. It is impossible to understand the achievements
and possibilities of electricity in locomotion without a certain amount
of discussion of both these points of view; but it is not necessary to
go deeply into either in order to catch some of the enthusiasm which
inspires the electrical engineer in his efforts to extend electric
traction everywhere on road and rail. The hopes of electrical conquest
extend, indeed, to locomotion on the sea and in the air as well as on
the land. At the root of these hopes there lies a firm faith in the
superior economies and flexibility of electricity as a mode of motion.

In the explanations which are given of electric tramways, electric
railways, electric automobiles, electric propulsion on ships, and the
other phases of electric traction, nothing but the most elementary
knowledge of electricity is presupposed. A certain amount of technical
description is unavoidable, but I have restricted it as far as possible
to essential matters which throw light upon the meaning of the various
systems of electric traction and explain the economic and physical
reasons for their adoption.

Anyone who glances over the history of electric traction will be struck
by the absence of outstanding names. There is no man who occupies the
same position in the sphere of electric locomotion as Watt does in the
world of steam, or Stephenson in the world of railways. As a pioneer,
Dr. Wernher von Siemens perhaps deserves more honour than any other.
But the leading ideas embodied in electric traction systems were
contributed by engineers who worked in the general field of electrical
engineering; and they have been applied and developed by a numerous
band of men who have added one brick of experience and ingenuity to
another until the imposing structure was made visible to the world.

Nevertheless, I hope the story as told briefly in the following
chapters will not be found devoid of human interest. It has the
advantage, at any rate, of the attraction which anything pertaining
to electricity holds for all sections of the public. This attraction
deepens upon closer acquaintance with the mechanism and the history of
electricity in action; and if any of the descriptions and forecasts are
found to be prejudiced in favour of a single instrument of locomotion,
the fault may be considered to rest with the spell which electricity
throws upon everyone who is concerned in any way with its applications
in the service of man.

I have to acknowledge the kind assistance of Mr. Frank Broadbent,
M.I.E.E., in looking over the proofs of this volume.

A. G. W.

_21 April 1911_

CONTENTS

PAGE

PREFACE vi

CHAP.

I. The Wheel and the Public 1

II. Early Tramroads and Railways 4

III. The Birth of Electric Traction 12

IV. The Essential Advantages of Electric Traction on
Tramways 19

V. The Mechanism of an Electric Tramcar: the Overhead
System 29

VI. Conduit and Surface-Contact Tramway Systems 37

VII. The Backwardness of Electric Traction in Great Britain 46

VIII. Electric Tramway Stagnation. The Trolley Omnibus 55

IX. Regenerative Control 67

X. Accumulator Electric Traction. The Electric Automobile 70

XI. Petrol-Electric Vehicles and main Marine Propulsion by
Electricity 82

XII. The Pioneer Electric Railways 92

XIII. Electric Railways from the Engineering Point of View 107

XIV. Electric Traction on Main Line Railways 116

XV. Curiosities of Electric Traction 124

XVI. The Future 138

INDEX 142

CHAPTER I

THE WHEEL AND THE PUBLIC

One of the greatest of unknown men of genius was the inventor of the
wheel. Probably--as in the case of most inventions--he shares the
credit with others who prepared the way for him by discovering that
heavy weights could be more easily rolled than dragged. But, whatever
the origin of the wheel and axle, the combination was so admirable that
it remained unchanged in its essential features for centuries and still
forms the primary element in locomotion.

Some of the earliest forms of vehicle can be found co-existing with
the very latest. In Oporto, for instance, there are electric tramways,
but there are also ox wagons which seem to belong to the childhood of
the world. The wheels are rigidly fixed to rotating axles (the oldest
known arrangement) and the supports of both the front and the back
axles are rigidly fixed to the wagon. The result is that the vehicle
cannot 'steer' and must be dragged round corners. Some time ago the
authorities, realising at last that this dragging was ruinous to the
road surfaces, made a regulation that all wagons should have their
front axles pivoted. This attempt at improvement caused more agitation
than the Revolution itself. The owners of wagons argued--with perfect
justice--that the rigid wagon had served for innumerable generations;
and they refused, in the face of fines, to make the change. Their
resistance was so general and so dogged that the law became a dead
letter, and the people reverted with great content to the ancient
system which divided the business of local transport between yoked oxen
and women who had been trained from girlhood to carry heavy loads upon
their heads.

This example of conservatism, though extreme, is characteristic of
the attitude of the general public towards innovations in locomotion.
Until mechanical power came to be used, there was--for many
centuries--nothing which could be described as a radical innovation in
transport. Roads were multiplied and improved; some advance was made
in the design and construction of carriages; and the organisation of
posting and stage-coach services was developed. But little more was
done. Compared with these superficial changes, the idea of using steam
power on the highway or on a railroad was so drastic a change that
it roused tremendous opposition. The railway companies fought this
opposition and overcame it, but the use of steam carriages on ordinary
roads was postponed until the appearance of the petrol motor encouraged
a movement--once more against strong prejudice--for the repeal of the
legislation which restricted the use of mechanically-propelled vehicles
on the roads. In a similar way horse tramways were violently attacked;
and their conversion to electric traction was opposed by a determined
minority in every town. More recently, there was a vigorous agitation
against the substitution of motor omnibuses for horse omnibuses in
London and elsewhere.

To some extent this recurrent opposition was reasonable enough. The
new forms of locomotion had dangers of their own; they were generally
noisy and sometimes dirty; and occasionally, as in the case of early
tramways, they were a nuisance to existing traffic. But it may be noted
that electricity claims to provide a means of locomotion not only more
rapid and more efficient (in most cases) than any other, but free from
many of the drawbacks which gave conservatism an excuse for opposing
the introduction of steam and other forms of locomotion.

In the following pages I hope to give a clear account of the
achievements of electricity in the field of locomotion and also to
indicate some of its more immediate potentialities.

CHAPTER II

EARLY TRAMROADS AND RAILWAYS

It has sometimes been remarked, by unfriendly critics, that tramways
are an apology for bad roads. That is to say, if road surfaces were
perfect, there would be no need to lay rails in order to allow vehicles
to run easily.

Although this view of the case may be no better than a quarter-truth,
it is justified to the extent that tramways were, as a matter of fact,
the outcome of an attempt to escape from bad road surfaces. In the
early days of mining, coals were taken by horsedrawn wagons from the
pits to the harbours. The passage and re-passage of heavy vehicles on
the same roadway led to the formation of deep ruts; and the first step
towards both the tramway and the railway was taken when logs of wood or
'trams' were laid in the ruts to facilitate transport.

The next step was to make the upper surface of the log round and the
rims of the wheels hollow, so that they fitted over the rails and kept
the wagons on the track. Owing to the upper part of the rails wearing
away quickly, thin plates of iron were in some cases nailed to them.
This improvement led to the adoption of a cast-iron rail, fastened to
wooden sleepers.

The earliest cast-iron railway was laid down before the middle of the
eighteenth century, about one hundred years after the first wooden
'tram-ways.' Half a century later we find the first rail-and-wheel
combination as we know it on modern tramways and railways, where the
wheel carries an inner flange and runs upon the head of a narrow metal
rail. This is the form which experience has proved to be best adapted
for safety, speed, and economy in power. The improvements made since
the beginning of the nineteenth century have been in matters of detail.

Many miles of colliery tramroads were in existence when--at the
beginning of the nineteenth century--the idea of using the steam engine
in place of the horse was taken up by engineers. They were concerned
at first solely with the carriage of coal; the idea of conveying
passengers arose at a later date, after the steam automobile had
been tried and abandoned for the time being. George Stephenson, for
instance, ran his first locomotives on colliery tramroads; and the
first railway--between Stockton and Darlington--was used for passengers
merely as an afterthought. It was, in fact, designed to be a tramroad
for the use of the public in general transport by horse traction.

The most curious feature of this stage in the evolution of locomotion
was that, although Stephenson's locomotives had been at work for
several years and although several schemes of iron roads had been
projected, very few people had any conception of the development
awaiting the locomotive and iron road in combination. They did not even
appreciate the proved fact that the locomotive was a more efficient
means of transport than the horse. An immense amount of pioneering work
had to be done before the impression of a new era could be borne in
upon the public mind. These were the days when the _Quarterly Review_
backed 'old Father Thames against the Woolwich Railway for any sum' and
when a witness before a Parliamentary Committee (on the Liverpool and
Manchester Railway Bill, in 1825) thought himself safe in suggesting
that a steam locomotive could not start against a gale of wind.

When these prejudices were overcome, many years had to pass before
the objections of landowners and citizens were worn down. Railway
engineers spent most of their time in a form of diplomatic warfare with
opponents to their schemes; huge sums--part of which still lingers in
the capital accounts of railway companies--were spent in Parliamentary
proceedings over Railway Bills. This barren process had to be repeated
when electric traction made its appearance; but happily the electrical
fight was not upon quite so extensive a scale, nor was the period
of preparation followed by anything comparable to the Railway Mania
of 1845, when the public made up for its early contempt of railway
enterprise by tumbling over itself to get shares in some of the most
crazy schemes which were ever put into shape by unscrupulous company
promoters.

The early history of the steam railway is interesting in connection
with electrical locomotion for two reasons. It shows that the railroad
proper evolved out of the tramroad or 'light railway,' as it would
now be called--a type of line which is specially suited to electrical
operation. It also includes a controversy between three modes of
traction; and this controversy forms a very good introduction to
a discussion of the reasons why electricity is so economical in
locomotion.

These three modes were (1) stationary engines: (2) locomotives: (3) the
device known as the 'atmospheric railway.'

In both the first and third, engine houses were placed close to the
line at convenient intervals. In the first, each steam engine operated
an endless rope to which the train of carriages was attached. The
system is still in use for colliery working and is also employed (in
an improved form, of course) for funicular railways. George Stephenson
himself employed it to assist locomotives up heavy gradients. In the
atmospheric railway the stationary engines were used to exhaust the
air from a length of cast-iron piping laid close to the railway. The
principle is the same as that of the 'pneumatic tube' which the Post
Office uses for sending papers over short distances. The papers are
placed in a cylinder which fits the interior of the tube; and when the
air is exhausted from the tube in front of the cylinder, the pressure
of the air behind it drives the cylinder forward.

Nowadays it is difficult to realise that such a system was seriously
proposed for railway work and actually adopted by an engineer of such
eminence as Brunel. But in point of fact it was recommended by two
Board of Trade experts in 1842 and by a Select Committee appointed in
1845 to consider several Bills for atmospheric railways. It was tried
at Dalkey and Croydon, and it was installed under Brunel's supervision
on a six-mile line in Devon. The carrier in the tube was connected
to the train through a longitudinal slit at the top of the tube. The
slit was closed by a leather flap, except when momentarily lifted by
the passage of the train. A great deal of ingenuity was exhausted in
attempting to make this 'longitudinal valve' efficient, but it was
found that heat, moisture, and frost made the leather deteriorate so
rapidly as to render it hopelessly ineffective in a short time. After a
series of misfortunes the atmospheric railway became a mere curiosity
in the history of invention.

Stephenson was right in regarding the atmospheric railway as 'only
the fixed engine and ropes over again, in another form.' He was also
right in his belief that the steam locomotive was more economical
than either of its rivals. But the stationary engine idea had the
germ of an even sounder principle than that of the locomotive. Both
in electric tramways and electric railways the power is obtained from
stationary engines. The main difference between the electric system
and the old rope and atmospheric systems lies in the superior economy
with which the power is conveyed electrically to the trains. There are
other important differences; but the essential point is that both rope
traction and pneumatic propulsion wasted so much power between the
engine and the train that their other advantages were annulled, and it
was found cheaper to put the engine on wheels and make it drag itself
as well as the train.

Brunel's reasons for his faith in the atmospheric railway are well
worth quoting for the light they throw indirectly upon the advantages
of electric traction. He argued that stationary power, if freed from
incumbrances such as the friction and dead weight of a rope, was
superior to locomotive power, on the following grounds:

(_a_) A given amount of power may be supplied by a stationary engine at
a less cost than if supplied by a locomotive.

(_b_) The dead weight of a locomotive forms a large proportion of the
whole travelling load, and thus inherently involves a proportionate
waste of power--a waste which is enhanced by the steepness of the
gradients and the speed of the trains.

Experience has proved the soundness of these principles. There has
been a steady improvement in the power and efficiency of locomotives,
but progress has reached a point at which further increases in speed
and accelerating power (a very important matter) are not attainable
without a prohibitive increase in the consumption of coal and a costly
strengthening of the railway track to stand the strain of heavier
engines pounding along at very high speeds. Electric traction, which is
a reversion in part to the stationary engine system, offers a means of
escape from the limitations of the locomotive.

There is still some doubt in the minds of railway engineers whether
electric traction is really superior to the steam locomotive on the
main railway lines, where distances are great and train loads heavy.
But the superiority is admitted on suburban lines and also on tramways,
where electricity has almost completely supplanted both horse and steam
traction. If Brunel had foreseen how economical electricity would be in
the transmission of power between engine and train, he would have felt
still more confident in his defence of the stationary engine.

CHAPTER III

THE BIRTH OF ELECTRIC TRACTION

The story of electric traction really begins in the laboratory
of Faraday. He was the first to produce mechanical rotation by
electrical means; and, although he had no practical end in view, his
investigations produced the germ of the commercial dynamo and thence of
the commercial electric motor.

That germ, however, took about half a century to develop. It is true
that in 1837 (about ten years after Faraday's discovery) Robert
Davidson experimented with an electric locomotive on the Edinburgh
and Glasgow Railway; it is also true that Jacobi, two years later,
propelled a boat on the Neva with electric power. But these early
attempts were not on a commercial scale. Not only was the motor a
crude contrivance, but the method of producing the electric power was
hopelessly extravagant.

At that period the 'primary battery'--similar in character to those
still used for laboratory purposes, ringing electric bells, and so
on--was the best available source of electricity. Such batteries
generate current by the chemical consumption of zinc. In order to
obtain sufficient power to move a boat, a large number of batteries had
to be coupled together. They were expensive in first cost, expensive in
the zinc which was their 'fuel'; and they became rapidly exhausted.

[Illustration: =DYNAMO= =MOTOR=
Fig. 1. Diagram to illustrate the essential identity of the dynamo
and the motor. The dynamo generates electricity when the armature or
group of coils is forcibly revolved close to magnets, thus converting
mechanical energy into electrical energy. The motor causes its
armature to revolve forcibly when current is supplied to it from the
dynamo. Thus the motor converts electrical energy into mechanical
energy.]

The essential step towards the commercial plane was taken when an
efficient means was devised for transforming mechanical into electrical
energy on a large scale. The first 'dynamo-electric' machines, invented
about the middle of last century, were merely hand machines. Their
power was limited by the strength of the permanent magnets employed in
their construction; and although an increase in power was obtained by
multiplying the number of magnets and driving by steam power, it was
not sufficient for commercial purposes. In 1867 electro-magnets were
first employed by Siemens and Wheatstone; and from this application
there was developed a machine whose power as a generator of electricity
was limited only by its size and the speed at which it was run.

It is unnecessary for our present purpose to enter into the technical
details of the modern electric generator and the modern electric motor.
The principles underlying them are quite simple, although the theory
of their design and the practice of their construction and operation
are almost a science in themselves. A dynamo or electric generator is a
machine for transforming mechanical into electrical energy; an electric
motor is a machine for transforming electrical energy into mechanical
energy. If, therefore, we place an electric motor upon a vehicle and
supply it continuously with current from a dynamo, the motor will
rotate and can be used to propel the vehicle. That is the essential
mechanism of electric traction.

The simplicity of the arrangement is enhanced by the fact that the
dynamo and the motor are virtually the same machine. In the dynamo, a
cylindrical 'armature' of coils is forced to rotate close to the poles
of electro-magnets; the energy exerted in turning the armature against
the influence of the electro-magnets is transformed into the energy of
electric currents in the coils of the armature. In the motor, which
also consists of an armature close to the poles of electro-magnets, the
process is reversed. When a current is passed through the coils of the
armature, the reaction between these currents and the electro-magnets
causes the armature to revolve.

This reversibility of the dynamo was, according to a story frequently
repeated, first discovered quite by accident. In a Paris exhibition a
number of Gramme dynamos--or dynamo-electric machines, as they were
then called--were being separately connected to lamps and other devices
for showing the effect of electric currents; and when one was started
up it was found that another was being _driven_ at a rapid rate.
Investigation showed that the second one had been coupled up to the
first by mistake and was therefore being worked as a motor by it.

This was in the year 1879; and the story of the incident served to
draw general attention to the discovery of a new and efficient means
of transmitting power. Engineers recognised that in the steam-driven
dynamo they had the means of producing powerful electric currents,
while in the electric motor, connected by wires to the dynamo, they
had the means of reproducing the power in mechanical form at a
distance. There were, of course, losses of energy in the process.
A certain percentage was lost in the dynamo itself, some in the
transmitting wires, and some in the motor. But the all-round efficiency
of the arrangement was much higher than that of any other system of
transmitting power from one point to another several miles distant.

In order to apply this system to propelling vehicles it was only
necessary to devise a continuous connection between the motor on the
vehicle and the stationary dynamo. This was done on the first electric
railway by means of a 'third rail,' substantially in the same way as
is now familiar on underground and other electric lines. The third
rail was a metal conductor supported on insulators and connected to
the dynamo. The vehicle or car was furnished with a metal brush or
skate which rubbed along the third rail as the car moved forward. The
current thus collected was led through the motor (which drove the axle
of the car through toothed wheels) and thence to the track rails, which
conveyed the current back to the dynamo and so completed the electrical
circuit. Messrs Siemens and Halske exhibited the first electric railway
of this type at the Berlin Industrial Exhibition of 1879.

Another method of collecting the current was tried soon afterwards
and formed the direct forerunner of the electric tramway on the now
standard 'overhead' system. The disadvantage of the third rail system
is that it involves an exposed 'live' conductor close to the ground.
It is therefore quite unsuited for use on streets. Consequently the
next step towards the electric tramway was to carry the electrical
conductors overhead by supporting them on poles erected at the side of
the track. The first installation of this kind was laid down at the
Paris Exhibition of 1881. In that case the conductor was an iron tube
with a slot along its lower side; and inside the tube was a 'boat'
which slid along and was connected to the car by means of a flexible
wire. A second tube, also with a boat and connecting wire, was provided
to carry the return current. We shall see later how this arrangement
evolved into the familiar 'trolley' system.

The mention of a slotted tube recalls the atmospheric system and,
in so doing, emphasises the superiority of the electric system in
simplicity, flexibility, reliability, and economy. Brunel's faith in
the advantages of stationary engines and the transmission of power
therefrom to moving trains would have been justified by the event if
the pneumatic system of power transmission had been as practicable as
the electric system. But there is an obvious contrast between the huge
pipe of the atmospheric railway, with its impossible 'longitudinal
valve,' and the small tube of the first overhead electric line or the
third rail of the first electric railway. There is also a pathetic
contrast between the prolonged struggles which Brunel and the inventors
of the atmospheric system underwent before they were forced to
acknowledge failure, and the rapid ease with which electric traction
entered into its kingdom when the commercial dynamo and motor were
first produced. The intrinsic difficulties which electric traction
engineers had to meet were not serious. Designers passed, step by
step, from the model electric railway at the Berlin Exhibition to
public lines on a larger scale, and from the model electric overhead
tramway to the 'street railway' or tramway which gradually supplanted
the horse tramway. Each step consisted in an extension of the distance
covered and an increase in the power required, coincident with a
gradual improvement in the details of motors, dynamos, and transmission
equipment.

CHAPTER IV

THE ESSENTIAL ADVANTAGES OF ELECTRIC TRACTION ON TRAMWAYS

A railway journal once committed itself to the statement that horse
traction was superior to electric traction on roads because the horse
possessed the 'vital principle' of energy in its constitution.

It is distinctly curious to find an authority on locomotion describing
the essential drawback of horse traction as its distinguishing
advantage. The 'vital principle,' unfortunately, needs food and rest
to maintain it not only during working hours but during the hours of
inactivity as well. In actual practice four horses out of every five in
a tramway stud are in the stables while the fifth is at work. Moreover,
the same stud has to be kept up, at a practically uniform cost, whether
the daily traffic be light or heavy. Thirdly, the 'vital principle' has
only a limited number of years during which--apart from sickness and
disease--it is effective for traction purposes.

[Illustration: Fig. 2. A typical electric tramway on the overhead
system.--The trolley standard carries the wires for supplying current
to the cars on both the up and down tracks. The driver has his left
hand on the controller handle and his right hand on the brake handle.
(Photograph reproduced by courtesy of Dick, Kerr and Company,
Limited.)]

Another disadvantage is that the pull which a horse can actually
exercise on a car is strictly limited and is only a small fraction of
the total power represented by the fodder which the horse consumes.
The strain upon a horse in starting a car or omnibus is so great that
a 'lover of animals' used to supply London omnibuses with appeals to
passengers not to stop the omnibus more often than was necessary,
especially on an incline. This was a recognition of the fact that the
horse cannot cope easily with the heavy strain at starting, and that he
requires assistance on heavy gradients.

It was not surprising, therefore, that on horse tramway systems
the speed was low, the cars of limited capacity, and the fares
comparatively high. The shortness of the journey which a tramway horse
was able to cover without fatigue also tended to limit the length of
routes.

On all these points electric traction was soon found to be distinctly
superior to horse traction. It was more economical in power; it was
able to maintain higher speeds with larger and more commodious cars;
and there was no narrow limit to the length of routes or the gradients
which could be surmounted. Consequently electric traction offered the
public an improved service at lower fares.

The whole of the power-producing plant for a typical electric
tramway system is concentrated at a generating station placed (if
possible) near the centre of the system. From this station runs a
network of electric mains to feed the lines with current at convenient
points. This concentration is a benefit on several grounds. A large
generating equipment is cheaper in first cost than a multitude of small
power-producing plants, and it is much more economical in operation.
If every car had its own power equipment, that equipment would need to
be powerful enough to haul itself and the loaded car up the steepest
gradient on the route. That is to say, the sum of the car capacities
would be equal to the sum of the maximum demands. But when the power
is obtained from a single stationary source we do away with the dead
weight of the power equipment on the car, and secure the very vital
advantage that the capacity of the stationary source need not be so
great as the sum of the maximum demands. In actual working it never
happens that all the cars are full of passengers and ascending the
steepest gradients simultaneously. While some are running up-hill,
others are going down-hill; while some are full, others are half full
or almost empty. The result is that the total demand for power at any
time is always very much less than the total of the maximum demands
made by each car; and the capacity of the generating station need be
sufficient to cope only with the smaller amount.

This advantage reduces the expenditure necessary upon boilers,
engines, and dynamos at the tramway generating station. And it is
enhanced by two valuable capabilities of the electric motor. The first
is its power of taking a heavy overload for a limited period without
injury. There is no difficulty about making an electric motor, whose
normal capacity is 20 horse power, give 40 horse power momentarily, 30
horse power for several minutes, and 25 horse power during the best
part of an hour. Applied to tramway work, this advantage means that the
rated capacity of the motor equipment of a car may be less than what
is required to haul a loaded car at an adequate speed up the steepest
gradient on the system. Such maximum demands, which only occur at
intervals with each car, can be met by the readiness of the electric
motor for overwork. The motors may therefore be reduced in size, saving
money in first cost and in the current consumed.

The second valuable peculiarity of the electric motor is that it gives
its 'maximum torque' at starting. That is to say, it exercises the
highest propulsive effort at the precise moment when it is required.
When horses are employed, they have to endure an abnormal strain in
overcoming the inertia of a stationary vehicle; everyone must have
noticed how horses have to struggle to start a car which they can keep
going at an easy trot once it has got up speed. The electric motor--to
use an apparent paradox--gives this abnormal pull as part of its normal
action. As the inertia of the car is gradually overcome, the speed of
rotation of the motor increases and its torque decreases, automatically
and precisely in accordance with the demands of the case.

The starting torque of a motor is such an emphatic phenomenon that
the driver of an electric car may, if he is careless and switches the
current on too suddenly, jerk any standing passenger off his feet, even
though the total weight of the car may be ten tons or more. Properly
employed, however, the electric motor gives an even and _rapid_
acceleration.

This is a far more important point in tramway economics than it
appears to be at first sight. The superiority of the electric tramway
over the horse tramway depends less upon higher speed than upon the
fact that less time is wasted in stopping to pick up and set down
passengers. Time is the vital element in all transport, and it is
especially vital in connection with tramways, which have to stop
with great frequency. If the time which elapses between putting on
the brakes at each stop and getting up to full speed again can be
materially shortened, then the average speed of the tramway journey can
be materially raised. It is easy, by means of powerful brakes, to bring
a car to rest quickly; the electric motor enables speed to be regained
quickly. In this way a high average speed may be maintained in spite of
numerous stops; and, with larger cars, the electric tramway is able to
handle a larger volume of traffic in a shorter space of time than the
horse tramway.

The time lost in stopping is of so much consequence that, when electric
tramways were introduced, the old custom of stopping the cars at
any desired point was abandoned. Stopping places were arranged at
convenient points along the route, some of them being regular stops
and others optional at a signal from passengers desiring to alight or
to board the car. The public soon got used to walking a short distance
to a stopping place, although they did not, perhaps, appreciate how
much the collection of traffic at a reduced number of points tended to
improve the general tramway service.

A high average speed with numerous stops was, however, only one of
the improvements which the public derived from electric traction.
Tramway passengers expect to find a car not only at a convenient point
but within a convenient period of waiting. With electric traction
the service became much more frequent than with horse traction. It
is quite possible to run a horse tramway service profitably with
cars at intervals of fifteen to thirty minutes, if the passengers
are patient enough to wait and fill each vehicle. But with electric
traction the main item is the cost of the standing equipment--the
power house, mains, and overhead lines--and unless that equipment is
adequately utilised the revenue will not cover the standing charges.
A fifteen-minute service is, generally speaking, the lowest economic
limit on an electric tramway. Every tramway manager tries to attract
sufficient passengers for a more frequent service; and, as a matter
of fact, it was found that where there was sufficient population the
provision of a frequent and rapid service encouraged tramway travelling
so much that cars had to be run at far shorter intervals than had been
customary on horse tramways.

The increase of traffic brought with it the demand for larger as well
as speedier cars with a shorter 'headway' or interval between one car
and another. The capacity of a horse car is limited by the fact that it
is not convenient to harness more than two horses to a single vehicle.
But with electric cars there is no extraneous limitation to carrying
capacity. Large double-decked cars with seats for seventy passengers
are now quite common. In America it is a frequent practice to attach
'trailers' to the cars, making a short tramway train. Experiments have
recently been arranged on similar lines in London, for the handling of
the heavy traffic at rush hours. These instances show that electric
tramway capacity is flexible and may be adjusted to the density and the
fluctuating character of the demand.

Finally, it falls to be noted that the power consumed by a tramcar
is, roughly, proportional to the useful work which the car performs.
As already mentioned, it costs about as much to work a horse tramway
when the cars are empty as when they are full, since the main item is
the maintenance of the 'vital principle' of a certain number of horses
independently of the traffic. But with electric traction the motors
require less power when the cars are running light. And less current
for the motors means less current generated at the power station--that
is to say, less steam, less oil, less coal, less wear and tear. If more
current is demanded, it is because more passengers are being carried
and more revenue earned.

Reviewing the subject broadly, it is apparent that the adoption of
electric traction on a tramway is not so much a step in advance as
a beneficent revolution. The higher speeds with more frequent, more
comfortable, and more commodious cars have created a volume of traffic
far beyond what could have been handled with horse traction. The change
also led to a great increase in the length of tramway routes and to
the construction of new tramway systems. In 1898, when the electric
tramway movement began in earnest, there were 1064 miles of tramway in
the United Kingdom. Now there are 2562 miles, and the number of tramway
passengers is more than double the total of third class passengers on
the whole system of British railways. The number of tramway passengers
carried during 1909-10 (the last period covered by the published
official returns) was equal to about 62 times the estimated population
of the United Kingdom.

While the traffic has multiplied in this remarkable fashion, there
has been a heavy reduction in the fares charged. This has been made
possible by the economical features of electric traction. In the
old days a horse tramway had to spend about £80 to earn £100; an
electric tramway need spend only about £60. With this reduction in
the proportion of expenses to receipts, and with the greater volume
of business, it became feasible to stimulate traffic still further
by giving passengers much longer distances for their money. In fact,
electric traction proved so economical that people began to imagine
that there was no limit to the reductions which might be made with
financial safety. However, there is plenty of evidence that a limit
exists. In many cases it has been touched, if not passed, but the
public continues to clamour for all sorts of concessions. These demands
are a great compliment to electric traction, but they are a decided
embarrassment to the tramway manager who believes in a reasonable
margin between his total expenses and his total revenue.

CHAPTER V

THE MECHANISM OF AN ELECTRIC TRAMCAR: THE OVERHEAD SYSTEM

A rough idea has already been given of the elementary mechanism of
electric traction--the combination of generating station, of cars
fitted with electric motors, and of a sliding contact between the two.
It is in connection with the sliding contact that the ingenuity of
tramway engineers has been mainly exercised. Three distinct solutions
were evolved for tramway work, giving rise to three systems--(1)
the overhead or trolley system; (2) the conduit system; and (3) the
surface-contact system.

The first system is now almost universal in the United Kingdom.
Part of the London system is equipped on the conduit system; and
the tramways at Lincoln and Wolverhampton are constructed on the
surface-contact system. Beyond these cases the trolley holds the field.
In the United States and on the Continent there is a larger proportion
of conduit work, but from a practical point of view it would hardly
be necessary to mention either conduit or surface-contact if it were
not for the great engineering interest which they possess and for the
controversies to which they have given rise.

[Illustration: Fig. 3. Diagrammatic illustration of the general
arrangement of an electric tramway on the overhead system. At the
foot is shown the generating station which supplies alternating
current at high-pressure (for economy in transmission) to a
sub-station where it is 'transformed' to low pressure and 'converted'
in a motor-generator to continuous current for distribution to the
trolley wire from which each car takes its current. The course of
the current through the trolley pole and controller and thence to
the motors and back by the rails is indicated by arrows.]

The overhead system has conquered because it is cheapest in first cost,
cheapest to maintain, most economical in current, and most reliable in
action. Later developments in surface-contact traction have run it very
close on some of these points, but have not--for reasons which will be
explained--affected the established position of the overhead system.

In its essential features the overhead system has not altered very much
from the experimental line erected at the Paris Exhibition of 1881. The
slotted tube has been replaced by a solid copper wire; and the 'boat'
sliding within it has been replaced by a wheel or a bow pressed against
the lower side of the wire by means of a pivoted arm controlled by
springs. The sliding bow is common on the Continent, but it has been
adopted on only one British tramway--that at Sheerness. Its use for
electric traction on railways will be mentioned later, but as far as
British tramways are concerned the bow is the exception which proves
the trolley wheel rule.

The function of the trolley wheel is to collect current from the wire
along which it rolls. This current passes through insulated wires down
the trolley arm to the controller, which the driver of the car operates
by means of a handle. The controller, which is really a series of
electrical resistances, is analogous to a water tap. By its means the
current may be completely shut off from the motors, or allowed to flow
in varying degree as required by the speed of the car. In starting a
car, the driver moves the controller handle notch by notch, so as to
get a uniform rise in speed until the full current is allowed to pass
through the motors. With such a mechanism, supplemented by brakes, the
driver has the movements of the car under control.

In a four-wheeled car, each axle is driven by a motor. In a bogie car
(one with a set of four wheels at each end) the axles of the larger
wheels of the bogie are each driven by a motor; but not directly.
Considerations of space make it necessary to keep the motor as small
as possible, but if a motor is to be small and also powerful it must
rotate at a high speed. On the tramcar, therefore, the motor drives a
small toothed wheel which drives a large toothed wheel fixed to the
axle, thus effecting a reduction of speed between the motor and the
wheel.

The same considerations of space join with others in making two motors
on each car the general rule. And the use of two motors enabled the
tramway engineer to introduce a refinement into the method of control.
This refinement is known as the 'series-parallel system.' One of its
objects is to give a large 'starting torque' and so enable the car
to gain speed quickly. When the current is first switched on by the
controller it passes through the motors in tandem or in 'series,'
thus dividing the pressure of the current (analogous to a 'head' of
water) between them. The starting torque of a tramway motor (or the
turning moment which it exerts when current is first passed through
it) is dependent on the current but independent of the pressure. Thus
the tandem or 'series' arrangement, which passes the full current
through each motor, gives the maximum starting torque without an
undue consumption of current. After the car is well started, the next
movement of the controller puts the motors in 'parallel,' opening up
two paths for the current instead of one, so that each motor receives
the full pressure. The practical result is that there is a very rapid
acceleration at starting, with marked economy in current. If the motors
were kept in 'parallel' right through, twice as much current would be
required to get the same starting torque. It will be seen later how
valuable this arrangement for getting a rapid start, without excessive
current consumption, may be in improving the physical and economic
conditions of a tramway or train service.

After having passed through the motors and done its work, the current
is led to the wheels of the car and returns by way of the rails,
which are linked together by copper bonds so as to form a continuous
conductor. The passage of the current from the wheel to the rail is
indicated by sparks when the rails are rough or very dry and dirty.
Although the rails, like the overhead wires, are thus carrying current,
there is no danger of shock from them, as the electrical pressure
in them is only a few volts, at the outside, while the pressure in
the overhead wires is 500 volts. It is this difference of pressure
which--like the 'head' of water in a turbine--supplies the motive power
for the car.

Each car on a tramway system may thus be regarded as a bridge which
completes an electrical circuit. When the driver moves his controller,
current flows from the generating station at a high pressure, passes
through the controller, operates the motors, and returns to the
generating station at a low pressure. This typical circuit is completed
through every car, so that the demand on the generating station at
any moment is the sum of the demands of the cars at that moment. The
business of the engineer at the generating station is to maintain the
electrical pressure in the overhead wire at the normal level of 500
volts; and in order to do this on an ordinary tramway system it is
found convenient to divide the overhead wire into half-mile sections,
each of which has a separate main or 'feeder' from the generating
station. The passenger can detect the change from one section to
another by the click of the trolley wheel across the gap which
insulates one half-mile section from another. At the same spot he can
see the short square 'feeder-pillar' at the roadside (containing the
switches by which current can be turned off from that section) and the
cables which pass along the arm of the trolley standard and terminate
in the overhead wire.

On an extensive tramway system the power-supply arrangements become
more complicated. The central generating station remains the primary
source of power, but sub-stations are erected at convenient points
between the central station and the outskirts of the tramway area.
These sub-stations are secondary stations for the distribution of
electricity. They receive power at extra-high pressure (5000 volts or
more) from the central station; they contain special machinery for
reducing the pressure to 500 volts for distribution to the various
tramway feeders. The object of this arrangement is partly technical
but mainly economical. Electric power can be transmitted at a lower
cost in mains and with less loss of energy at high pressures than at
low. Consequently when the termini of tramway routes are several miles
from the generating centre, greater all-round efficiency is secured
by transmitting current at high pressure to a number of well selected
sub-stations.

[Illustration: Fig. 4. Photograph of a car on a conduit section of
the London County Council tramways. The centre line on the vacant
track indicates the slot rail through which the 'plough' on the car
passes to make contact with the conductors in the underground conduit.
(Photograph reproduced by courtesy of Dick, Kerr and Company, Ltd.)]

CHAPTER VI

CONDUIT AND SURFACE-CONTACT TRAMWAY SYSTEMS

Roughly speaking, the arrangements for generating electricity,
distributing it, and utilising it on the car, remain the same in
conduit tramways and surface-contact tramways as on the overhead
system. The differences between the three systems are, as already
indicated, confined to the means of collecting the current for each car.

Both the conduit and the surface-contact system were suggested as a
means of escape from the main objection to the overhead system--the
exposure of 'live' wires in the street. The cable tramway, with its
concrete trough and slot, gave an obvious hint. There would be no
difficulty, apparently, in carrying wires on insulators in the trough
or conduit, and utilising the slot for a 'plough' which would slide
along inside the conduit, keeping contact with the wires, and so
conveying the current to the car.

This was tried for the first time in Blackpool, where--in 1884--a
length of conduit tramway was laid along the front street of the town.
The conditions could hardly have been less favourable for the system,
as the sea frequently washed over the roadway, flooding the conduit
with water and sand. Further, the conduit was so shallow that children
were able to get at the conductors with their metal spades. As the
conduit carried the return wire, the effect of a metallic contact
between the two conductors was to cause a 'short circuit,' with very
entertaining fireworks but with no amusing results for the tramway
engineer. After a heroic trial, the system had to be abandoned.

Bournemouth was the next British town to adopt the conduit. It did so
as a token of its exceptional civic pride. Three times, in fact, the
Bournemouth Corporation declared that it did not want tramways of any
kind whatever within its gates. And when the pressure of public opinion
forced its consent, the arrangement was made that no overhead wires
should appear in the central district of the town. Several miles of
conduit tramway were therefore constructed (the trolley system being
used for the outer tramway routes); and as by that time a good deal of
experience had been gained in conduit work both in America and on the
Continent, the contractors were able to give the Corporation a conduit
system built to endure. At first the Corporation was reconciled to the
fact that the conduit sections had cost about twice as much per mile as
the trolley lines, but as years went on, and as the financial results
of the system continued to prove unsatisfactory, the Corporation's
contentment became modified. An examination of the accounts showed that
the conduit sections could be reconstructed on the overhead system at a
cost equal to the annual expense of maintaining these sections in good
working order. Since the public had got used to the overhead wires on
the other sections, and since they had not got used to owning tramways
which produced a heavy loss, the decision was made to abandon the
conduit system altogether.

In London the conduit system was adopted by the London County Council
for various reasons. One was that the Council felt that London ought
to have the best, the very best, and nothing but the best. Another
was that the streets were so congested with traffic, lamp standards,
telegraph and telephone poles, and other obstructions, that trolley
wires and trolley standards would be a great nuisance and a serious
danger. Aesthetic reasons were also advanced, but it is difficult to
realise that they had much weight in connection with the majority of
metropolitan streets. Trolley wires were, in fact, freely erected in
suburban streets where there was a certain amount of beauty worth
preserving.

The main underlying reason, no doubt, was the feeling that London could
afford the most costly system. In any ordinary city (and perhaps in
London as well) the conduit must be regarded as a luxury. It involves
a continuous road excavation so deep that a great deal of incidental
work has frequently to be done in moving gas, water, and drain pipes
out of the way. The conduit itself is a thick channel of concrete,
strengthened at intervals of a few feet with heavy cast iron 'yokes'
which support the 'rails' forming the lips of the slot through which
the 'plough' of the car passes. Elaborate arrangements have to be
made for draining the conduit, as any accumulation of mud or water
in contact with the conductors, or the special insulators supporting
them, would be fatal to the working of the system. And in practice
the ordinary drainage has to be assisted by continual scraping of the
conduit with special brushes and by repeated flushing during the hours
when the cars are not running. Heavy rains and snowstorms are therefore
liable to upset the working of the system; and the tramway manager has
to employ quite an army of men simply to keep the conduit in working
order.

Trouble is also apt to be caused by purely mechanical means. On
one occasion a child's hoop fell through the slot and caused a short
circuit. As the ordinary scrapers slipped over the hoop, its presence
was not detected for a considerable time, during which the tramway
service was at a standstill. Altogether there is a greater liability to
interruption on the conduit system than on the overhead system.

[Illustration: Fig. 5. The upper portion of the illustration shows a
section of a typical conduit system of electric tramway traction.
This section is taken at one of the cast-iron 'yokes' which support
the rails forming the slot through which the 'plough' passes from
the car to make contact with the conductor rails.

The lower illustration gives a longitudinal and transverse section of
the 'G-B.' system of surface-contact tramway traction. The rope-like
cable carries the current and is supported on insulators. When the
collector on the car covers the stud, the action of the magnet draws
the lower part of the stud into contact with the cable, thus supplying
current to the car. After the car has passed, the lower part of the
stud rises by the action of a spring and, breaking contact with the
'live' cable, becomes dead. (In actual practice contact would be made
under the conditions shown in the left-hand diagram.)]

Experience of these drawbacks led the London County Council to seek
an alternative to the conduit when constructing electric lines in the
north of London. Many of the borough councils, following the County
Council's own previous arguments, would not listen to the suggestion
of the overhead system; and a freshly-elected Council, pledged to a
policy of economy, determined to try the surface-contact system. How
this trial gave rise to a violent political controversy, leading to
the abandonment of the project and culminating in important libel
actions, forms a picturesque story which need not be told in detail
here. Its main interest lies, for the moment, in the emphasis which the
incidents give to a characteristic of the surface-contact system--its
sensitiveness to minute alterations in detail.

The surface-contact or 'stud' system is really a modification of the
conduit system. It has, in fact, been called the 'closed conduit.'
The electric wires are again placed in a channel or pipe underground,
but instead of being accessible through a slot, contact can be made
with them only through metal studs placed at intervals flush with the
roadway. By special electro-mechanical devices in the stud and on the
car, the stud is brought into contact with the 'live' underground wire
only when the car is over it. That is to say, the studs covered and
protected by the car will be 'live' and supplying power to the car
through a sliding brush or 'skate,' while those not so protected will
be 'dead' and therefore of no danger to the public.

An immense amount of ingenuity has been expended by many engineers in
devising studs to act with absolute certainty under all conditions.
In the laboratory or the workshop, and even on an experimental track,
it was simple enough to arrange a mechanism which would 'make' and
'break' contact with admirable regularity. But when it came to putting
the mechanism down on an ordinary roadway, to be covered with mud,
pounded by heavy traffic, and subjected to the action of damp, frost,
heat, and all sorts of unexpected influences, much less satisfactory
results were obtained. Time and again the hopes of engineers were
dashed by a succession of petty troubles--some of them obscure, most
of them unforeseen. The weak points in nearly all the systems were the
insulation of electrical parts and the road construction work. Lack
of simplicity and rigidity led to the introduction of moisture and to
the shifting of parts so that studs jammed and remained 'alive' after
the car had passed over them. But even after the practical elimination
of these troubles the success of the surface-contact system seemed as
sensitive as the system itself.

One system was tried at Torquay, and discontinued after a protracted
trial on a large scale. Another system--the Lorain system--was
installed at Wolverhampton and is still in operation, but without
imitators. A third system--the Griffiths-Bedell or G-B. system--was
installed in 1905 at Lincoln, with satisfactory results. It was the
G-B. system which was offered to the metropolitan borough councils as
an alternative to the conduit and the trolley. A trial section was
laid down in 1898 in the Bow Road, and a certain amount of trouble was
experienced with live studs and with various parts of the equipment.
Owing to the stud system having been suggested by the Moderate Party,
the experimental difficulties were extensively advertised by members
of the Progressive Party, who condemned the system as dangerous and
unworkable. Public feeling was worked up to such a pitch that, in the
face of expert advice in favour of the system in a somewhat modified
form, the Council decided to abandon the experiment. Libel actions by
the owners of the 'G-B.' patents followed, part of the plaintiffs' case
being that the system as laid down was altered in a number of small but
vitally important details by the Council's officers and was therefore
not the 'G-B.' system proper.

The results with the 'G-B.' system at Lincoln prove that it is
possible to construct surface-contact tramways at a cost about 10 per
cent. more than that of trolley tramways, and to operate them, safely
and with reliability, at a cost not appreciably more than the general
working expenses of an overhead line. But this proof has not only been
enfeebled for the special reasons just described, but it came at a time
when the public had got quite accustomed to the trolley and also when
most towns had already been equipped with electric traction. Ten or
fifteen years earlier, such a proof might have changed the course of
tramway development; now it can have no great material effect.

The upshot of the contest between the three systems has, therefore,
been the survival of the one which was most despised at the outset.

CHAPTER VII

THE BACKWARDNESS OF ELECTRIC TRACTION IN GREAT BRITAIN

Popular objections to the overhead system are not, of course, quite
dead. Every tramway proposal in districts where the trolley has not
already penetrated is still opposed on the ground of disfigurement
and danger. This opposition serves as an index to the severity of the
struggle which the advocates of the trolley system had to encounter
before they made it almost universal in large cities. But the dislike
of the public for a questionable novelty was not the sole reason why
electric tramway enterprise was backward in Great Britain.

It is not strictly accurate to say that electric tramway _enterprise_
was backward. The enterprise was there, in spirit, but circumstances
were very much against it. Tramway schemes are controlled by special
legislation which was passed before electric traction was contemplated;
and this legislation has not been amended in any material degree to
suit the altered conditions brought about by the use of electricity.

The Tramways Act, 1870--which is the master Act of the situation--was
framed at a time of reaction against public monopolies. Before that
time, gas, water, railway, and other companies had been granted
statutory powers in perpetuity; and when a local authority wanted to
take the supply of gas or water into its own hands, it had to buy the
existing undertakings at the valuation put upon them by the owners
themselves. There were frequent complaints about excessive purchase
terms, and also about extortionate rates charged by the monopolist
companies. Consequently, when horse tramways came on the scene, the
legislature determined to put the new 'monopoly' on quite a different
basis. The Tramways Act provided, first, that no application for
tramway powers would be so much as considered if it did not gain the
consent of the local authorities interested; second, that the period
of tenure should be limited to twenty-one years; and third, that the
local authorities should have the option, at the end of the period or
at seven-year intervals afterwards, of buying the tramway undertaking
at the 'then value' of the plant (rails, horses, cars, depots, etc.)
without any allowance for compulsory purchase, goodwill, future profits
or any other consideration whatsoever.

This Act was passed with the very best of intentions. It had the
advantage of substituting, for the costly and clumsy procedure by
Private Bill, the simple and cheap process of applying to the Board
of Trade for a 'Provisional Order' which would acquire the full
force of an Act when ratified (in a more or less automatic way) by
Parliament. But in spite of its good intentions it proved a serious
stumbling-block, especially when electric traction was proposed.

The effect of the limited tenure system, with compulsory expropriation
on what were called 'scrap-iron' terms, was to make the companies very
reluctant to spend one penny more than was absolutely necessary during
the concluding years. Capital expenditure on improvements in equipment
was regarded as out of the question, since there was not sufficient
time to recoup the difference between first cost and the 'then value'
at the purchase period. Money was grudged for the upkeep of track, the
repair and painting of cars, and the hundred and one items of expense
which are essential to a well-conducted tramway. System after system
fell into a state of shabby gentility, hoarding money against its
inevitable end.

This was the condition when, in the middle eighties, electric traction
was suggested. The public, suffering from the decay of the tramway
service, but not realising that the cause lay with an Act devised for
the public benefit, expected the tramway companies to adopt the new
mode of propulsion. But as the conversion to electric working involved
track-work costing several thousands of pounds per mile, and new cars
costing several hundreds each, together with a large generating plant
and new car depots, the change was commercially impossible to companies
which were forced to retain their old horse equipment in order to
realise something for the shareholders in the day of expropriation.
From these causes there arose a demand that the municipalities should
take over the tramway systems and do what the companies appeared too
slow to undertake.

Thus a strong impetus was given to municipal tramway enterprise. But
this impetus did not remove the causes of delay. The local authorities
had good economic reasons for waiting until the existing tramway leases
ran out and so enabled purchase to be made upon the most advantageous
terms. They were also obliged to move very cautiously in adopting so
radical and so novel a change as electric traction. Municipalities are
not speculative traders, who are ready to take risks after a rapid
expert investigation of a new policy. Further, no municipality likes to
accept the decision of another as valid for its own district.

The consequence was that each municipality thought it necessary to
get its own expert report on the subject and, in many cases, to send
its own deputation to inspect Continental tramway systems. These
preliminary studies, with debates in Council chambers and newspaper
columns, with public meetings of encouragement or protest, and with the
erection of experimental lines, took up so much time that little of a
substantial nature was done until several years after engineers were
ready and willing to carry out the conversion of large systems of horse
tramways to electric working.

The municipalities, however, were not the only forces at work. Towards
the year 1896, when a large number of tramway leases were running out,
a considerable amount of business was done by private capital in buying
up horse tramways with a view to conversion and also to extension far
beyond the limits of the existing routes. The essential condition of
the success of such enterprise was, of course, the renewal of the
tenure of the tramways for at least another twenty-one years. Here--and
in the accompanying applications for extensions of route--the true
inwardness of the Tramways Act was shown. Everything was in the hands
of the local authorities. They had only to withhold their consent, and
nothing could be done. And this power of veto enabled them to drive any
bargain they pleased with the promoters of tramway schemes.

Most electric tramway proposals covered the areas of several local
authorities, so that negotiations had to be entered into with each in
turn. The municipalities, being the guardians of the public interests,
considered it their duty to impose the heaviest conditions which
the promoters could be induced to accept, rather than abandon the
enterprise. It was a case of Hobson's choice in every parish. In some
instances direct payments for wayleaves were demanded. In others the
promoters were forced to bear the cost of street widenings and other
'public improvements' which were not always necessary for tramway
purposes. In nearly every town the fares and stages were determined by
the local authority--on the strength of the veto, not on commercial
principles. The cost of construction was frequently increased by
onerous conditions regarding the standard of overhead wire and track
work. Under the Tramways Act, tramway companies were compelled to
maintain the roadway between the rails and also outside for a space of
eighteen inches--a provision which was sensible enough when horses were
used. But the condition was not only enforced within these statutory
limits when the promoters were about to use a form of traction which
spared the road surface; it was extended in numerous cases to an
obligation to pave the entire roadway and to maintain it--often with
expensive wood paving where macadam had previously been considered
quite good enough for the traffic.

One effect of this state of affairs was delay. The preliminary
negotiations with local authorities--the interviews with mayors,
aldermen, councillors, town clerks, and borough surveyors, to say
nothing of the 'frontagers' along the line of route--usually occupied
far more time than the actual construction of the tramways. They were
also much more troublesome, since it was within the power of a single
local authority in a central position to 'hold up' a complete scheme,
while most districts had strong local patriotism and wanted a municipal
system to themselves. Very little is known by the general public of
the anxiety, difficulty, and expense attending such negotiations
with local bodies divided into parties or cliques and furnished with
an absolute power of veto. Looking back on the history of electric
traction, it really seems extraordinary that engineers and financiers
had the patience to undertake this work and carry it through. Their
reward, as will be seen, was not great in a pecuniary sense; and, as
regards reputation, they are generally accused of being extravagant,
avaricious, and wanting in enterprise.

The ultimate effect was that the actual cost of electric tramways
exceeded the estimates prepared on the basis of Continental and
American experience. The more prolonged and difficult the negotiations
preliminary to a scheme became, the greater the expense. And the
conditions imposed by local authorities as the price of their consent
loaded the capital account of electric tramway undertakings with items
which had no direct concern with the tramway. The Board of Trade
assisted the increase in cost by prescribing a standard of construction
which was higher than that allowed in other countries. The net result
has been that while electric tramways were expected to cost about £9500
per mile, they have actually cost over £12,000 per mile.

The revenue side of the account has also been affected by the power
of veto. A local authority has no hesitation in imposing low fares
and long stages (with high wages and short hours for employees) upon
a tramway company seeking its consent. The standard usually adopted
is that of large urban systems with dense traffic, so that systems in
scattered districts are often unfairly treated. In municipal systems
themselves the fares are apt to be determined by the promises of
councillors at election times rather than by the simple consideration
of a fair price for improved traffic facilities. Workmen's fares, for
instance, are a dead loss on practically every tramway system. Every
now and again there is an agitation for halfpenny fares, for the
extension of stages, for cheap rates for school children, for free
transport for the blind, and so on. A leading municipal tramway manager
once remarked that it was almost impossible for men in his position to
resist the pressure for such concessions, especially at local election
periods. The chairman of the Highways Committee of the London County
Council recently stated that never a day passes without some appeal for
concessions in tramway fares.

Most of the large urban systems are under municipal control, and
therefore they have the rates in reserve, as well as the most
favourable traffic conditions, to encourage them in giving the public
more and more for less money. But the tramway companies, working for
the greater part in less thickly populated areas, with no extraneous
means of making up losses, are put in a difficult position when similar
concessions are forced upon them. The upshot is that the average return
on the capital of electric traction companies amounts to only 3·41 per
cent. Better profits were, in fact, made in the horse tramway days; and
the electric traction industry is a fine example of the way in which
the enterprise of engineers and capitalists may bring little comfort
to themselves but enormous benefit to the public, which shows its
gratitude by asking for greater blessings at their expense.

CHAPTER VIII

ELECTRIC TRAMWAY STAGNATION. THE TROLLEY OMNIBUS

The revenue of a tramway is built up of pennies; and a minute increase
in the average earnings per passenger will therefore have a large
effect on the total receipts. For instance, it was calculated (in
1907) that an increase of one-tenth of a penny in the average fare on
the sixty systems under the control of the British Electric Traction
Company would mean an increase of over £200,000 in the revenue.
Similarly, a fractional decrease in one of the operating expenses--say,
the cost of electric current--might transform a shaky undertaking into
a sound one. Tramway finance, in fact, is a question of infinitesimals.

So long as fares are determined by arbitrary conditions, little can
be done to increase the revenue on an electric tramway system. Such
matters as the weather and the extent of building operations have far
more influence on tramway traffic than anything the tramway manager can
do to assist it. Apart from the development of parcels traffic, his
best opportunities lie in the skilful adjustment of the service to the
varying needs of the public, so that the 'rush' hours find an adequate
supply of cars, while the quieter hours find no 'waste car mileage'
in the form of empty cars. He can also do a good deal in the way of
inducing the drivers not to waste current. By putting an electricity
meter on each car it is possible to check the current consumption and,
by a system of bonuses, to encourage the economical driver. There
are many other directions in which small financial leakages may be
arrested, giving an aggregate saving which is well worth the trouble.

[Illustration: Fig. 6. Photograph of an electric trolley omnibus
built by the Railless Electric Traction Company Ltd. in 1909 and
operated at Hendon for experimental purposes. Later cars built by
this company are of a lighter and simpler design, but the illustration
shows clearly the arrangement of a double trolley for supplying
current to a vehicle which 'steers' like an ordinary motor omnibus.]

The fact remains, however, that on the whole the electric tramway
business depends upon too narrow a margin between costs and receipts.
The recognition of this fact, coupled with the legislative difficulties
already described, led to the practical cessation of tramway
development in Great Britain at a point far short of what was once
expected. At one stage, no doubt, people were a little too enthusiastic
about electric traction. They imagined that electric traction would
create profitable traffic along the most deserted of side streets.
Acting on that theory, municipalities constructed--or forced tramway
companies to construct--lines along roads which could never supply
enough traffic to justify the expenditure involved. The interest on
capital and other standing charges for an electric tramway route are so
substantial that a certain minimum of traffic density must exist before
any profit at all can be earned.

However, after every allowance is made for such local excesses of
enthusiasm, the under-developed condition of electric traction in
Great Britain remains conspicuous enough. A sensible relaxation of
legislative restrictions would go a long way to improve matters--if,
that is to say, financiers could be induced to re-enter a field in
which they have had many disappointments.

Great hopes of improvement were entertained when the Light Railways
Act, 1896, was passed. The primary object of this Act was to encourage
the building of cheap railways for agricultural and fishery purposes,
but it was drafted on lines broad enough to include electric tramways.
Arrangements were made for State and local contributions to the cost of
such schemes, in cases where subsidies appeared to be justifiable. The
procedure in obtaining powers was made as simple and as economical as
possible. Applications for 'Light Railway Orders' had to be made to the
Light Railway Commission, one of whose members then arranged to hold a
local inquiry into the proposal. If sanctioned, the scheme was passed
on to the Board of Trade for approval, and the Order, if confirmed,
thus secured the validity of a Private Act of Parliament.

Nothing was said in this Act about the consent of local authorities, or
about limited tenure, or about expropriation upon scrap-iron terms. But
the Light Railway Commissioners chose to interpret the Act in terms of
the Tramways Act, with the result that, when there was any opposition
on the part of local authorities, the tramway promoter using the Light
Railways Act was not much better off than before. He had to face a new
difficulty in a clause of the Light Railways Act, which provided that
when the proposed light railway was of sufficient magnitude and in such
a position that it offered competition with an existing railway, the
scheme should be submitted to Parliament as a Private Bill--that is to
say, should face the most costly and cumbersome procedure of all.

The Light Railways Act thus proved a great disappointment. Its failure
to afford relief seems to have taken away the tramway promoter's last
hope of genuine legislative betterment. He has resigned himself to
things as they are; and the utmost he does is to assert, when occasion
offers, that there are many districts which might enjoy the benefits
of electric traction if means were provided for bringing every scheme
directly before an independent tribunal for consideration on its merits
alone; if arrangements were made for obtaining wayleaves and land on
favourable terms, and if he were allowed to construct and equip the
line on a less costly basis than the Board of Trade now demands, even
in rural districts.

Pending that revolution, tramway authorities are seeking to develop a
cheaper means of electric traction than the tramway. At the present
stage, urban tramways have spread through suburbs towards villages
and small towns which are anxious for better transport facilities
but have not sufficient population to justify a tramway extension.
Inter-urban tramway systems--those connecting towns with a network of
lines--are also adjacent to such minor centres of traffic. From time
to time attempts have been made to meet the demand by means of petrol
omnibuses, but they have rarely been successful--partly, no doubt,
owing to the difficulty of working a limited petrol omnibus service
economically at the extremities of an electric tramway system.

The latest solution of the problem is the 'trackless trolley' or, more
correctly, the 'trolley omnibus.' In the 1911 session over a dozen
tramway authorities applied for powers to use this device; and, if the
financial results of the first attempts are successful, there will
probably be a considerable growth in this type of electric traction.

The trolley omnibus is a hybrid between the trolley tramcar and the
omnibus. It is akin to the first, because it derives its power from
an overhead wire through a flexible trolley pole. It is akin to the
second, because it does not run on rails but is fitted with solid
rubber tyres and uses the surface of the road in the usual way.

Roughly speaking, its electrical equipment is similar to that of
a tramcar. The trolley pole conveys the electric current to the
controller, which admits it to motors geared on to the back axles.
There are, however, one or two important differences. The absence of a
rail which might act as a return conductor necessitates the provision
of a second overhead wire and a second trolley-pole to connect with it.
Thus the electrical circuit is from the power station, along the first
overhead wire, down the first trolley-pole, through the controller and
motors, up the second trolley-pole, and back by the second overhead
wire to the power station. Owing to the vehicle being a steerable
one, the trolley-poles have to be specially designed to give plenty
of free play sideways. The vehicle itself is similar in appearance to
a single-decked motor omnibus, and it runs on solid rubber tyres or
spring wheels.

The first thing which strikes one about the trolley omnibus in
comparison with the electric tramcar is the cheapness in first cost.
All the expense of concrete foundations, heavy rails, and granite
paving is avoided. On ordinary roads the overhead construction is
much less costly, as a single line of poles supporting two wires is
sufficient for the up and down services. Estimates show that the
equipment of a mile of roadway on this system will cost only from
one-fourth to one-third of the corresponding tramway system. Following
on this economy there is the saving in the cost of maintenance and
repairs--a serious item on the ordinary tramway. In actual working, the
system has the advantage that the vehicles can steer past slow-going
traffic, thus avoiding the delay caused on tramway systems through
carts having to draw out, away from the track, when overtaken by cars.
This steering or 'overtaking' power enables a trolley omnibus service
to be maintained without obstruction on a narrow roadway which would
be badly congested by tramcars running on a rigid track. When there
is only one pair of wires, two trolley omnibuses may pass each other
(whether going in the same or opposite directions) by the simple
process of pulling down the trolley poles of one car and swinging
them out of the way for a few seconds. On a single-line tramway it is
necessary to provide loops at intervals for crossing purposes and also
to arrange the service so that cars arrive at the loops simultaneously.

The other side of the picture is shown when we come to look into the
costs of working.

No matter how good the road surface may be or how excellent the design
of the wheel, the tractive effort required for a trolley omnibus
must be relatively greater than that required for a tramcar. Nothing
demands a lower tractive effort than a steel wheel running on a steel
rail. Consequently the trolley omnibus takes more power per ton moved
than the tramcar. When the road surface is wet or uneven, or muddy
or loose, this difference is of course multiplied. Another addition
to the working cost is produced by the tyres, which, if of rubber,
may wear away at the rate of 1-1/2_d._ or 2_d._ per mile per vehicle.
Owing to the uniform control of speed afforded by the electric system,
there is less jerking at starting or stopping than is general with a
petrol-driven omnibus; but in spite of that advantage, tyre wear on a
trolley omnibus must remain an important item. Something must also be
allowed for the effect of vibration upon the car body and electrical
equipment--an effect which is of course much less pronounced when a
vehicle runs on rails.

The balance between these advantages and disadvantages is not easy
to strike, even on a general basis. And it varies so much under local
conditions that tramway engineers debated a long time before they
decided in certain cases to try the trolley omnibus in extending their
traffic facilities. All they had to go upon was the experience gained
on certain Continental routes, where trolley omnibuses have been
running for several years. That experience encouraged the hope that
trolley omnibuses might be a profitable means of developing traffic in
conjunction with a tramway system, and along routes which would not
provide sufficient business for a regular tramway.

The simultaneous adoption of the trolley omnibus on a number of tramway
'feeders' gave rise to an impression that tramway authorities had
discovered the wheel-on-rail system to be less efficient than the
tyre-on-road system. As a general proposition, nothing could be further
from the truth. Tramway authorities have adopted the new system in
certain cases where the possible traffic is comparatively small, not
as a substitute for tramways, but as an alternative to self-propelled
omnibuses. The carrying capacity of a trolley omnibus is about twenty,
while that of a tramcar is frequently as high as seventy. The speed of
a tramcar runs up to twenty miles an hour, while twelve miles an hour
is as much as is comfortable (to say the least) with a vehicle running
with solid tyres on an ordinary road.

Therefore, where large volumes of traffic have to be handled swiftly,
the tramway will remain. But where a twenty-minute or half-hourly
service of small vehicles is sufficient for the available passengers,
a system which is much cheaper in first cost is clearly more suitable,
even though it may not reach the standard of economy in working set by
the large urban tramway. That is to say, the choice between the two
systems depends entirely upon local circumstances.

[Illustration: Fig. 7. The 'auto-trolley' system of electric traction
applied to the haulage of goods in a German quarry. (From _Electrical
Industries_.)]

As an emphasis upon this statement, it is significant that many
tramway engineers regard the trolley omnibus merely as the forerunner
of a tramway. For this reason they favour the adoption of the
particular trolley omnibus system where the overhead equipment is
adaptable with trifling changes to tramway purposes. They argue that,
in the case of a village of a few thousand inhabitants, situated a mile
or so beyond the terminus of a tramway route, a trolley omnibus service
will not only be sufficient for the existing traffic, but will show
whether the traffic is likely to increase (through the stimulation of
building enterprise) up to the point where it would make the laying of
rails worth while. When that point is reached, the rails will be laid
and the trolley omnibus vehicles put on some other route which is at
one and the same time a tramway 'feeder' and a tramway 'feeler.'

CHAPTER IX

REGENERATIVE CONTROL

Before going on to discuss the 'accumulator' or 'storage battery'
system of electric traction, reference should be made to an invention
which holds the germ of great economies in electric traction. This
invention is known under the name of 'regenerative control.'

It has already been explained that the dynamo is reversible--that is
to say, a dynamo may act as a motor, or a motor as a dynamo. This fact
is usefully applied in braking tramcars. When a car has gained speed,
its momentum represents a certain amount of stored energy. In stopping
the car, this energy has to be absorbed or dissipated in some way or
other. One method is to utilise the friction of brake blocks on the
wheels, or of skids on the rails themselves. With the electric car,
however, it is possible to absorb the energy by making it drive the
motors as if they were dynamos. The moving car drives the wheels, which
in turn drive the motors; and the current so generated may either be
absorbed in electrical 'resistances' or led to electro-magnets which
are so placed that they exercise a retarding pull on the rails. In any
of these cases a car which is being stopped, or is being 'held back'
by the brakes when going down-hill, is wasting power. It is clear,
therefore, that a great deal of power could be saved if the current
generated by the motors in retarding could be pumped back, as it were,
into the electrical circuit.

This is the problem of 'regeneration' which has fascinated many
electrical engineers. The practical difficulties underlying it are very
great; and perhaps the only man to get within measurable distance of
surmounting them was Mr J. S. Raworth, whose system of regenerative
control was tried on a number of tramway systems and installed on the
Rawstenstall tramways in 1909. It cannot be said with confidence that
all the difficulties have been overcome; on the other hand, it would
be rash to say that they are insurmountable. Mr Raworth, at any rate,
retains his faith in ultimate victory; and the theoretical beauty of
the system is so complete that it is bound to retain its fascination.

The practical result of regeneration is to eliminate the effect of
hills. A regenerative car in descending a hill gives back to the
generating station some of the excess energy required to take it up the
hill. In the same way each car, in coming to a standstill, gives back a
portion of the energy required to start it. A regenerative tramway may
thus be represented, from the energy point of view, as one in which all
the cars are running at normal speeds on level roads.

Incidentally the regenerative system gives a very perfect control
of the speed of the car on all gradients, owing to the regeneration
which begins automatically when the motors start 'coasting.' It is a
power-saver and a brake in one; and its efficacy as a means of control
is so great that, if its incidental drawbacks could be avoided, it
would be worth adopting for this purpose alone, both on electric
tramways and on electric railways.

CHAPTER X

ACCUMULATOR ELECTRIC TRACTION. THE ELECTRIC AUTOMOBILE

The use of the accumulator or storage battery in electric traction
affords a very good example of how a means of propulsion may fail
in one set of circumstances and contrive to succeed in another. Its
history serves to remind us that the problem of cheap transport is
really a group of problems, each one of which demands a particular
solution.

The accumulator is a device for storing electrical energy in the form
of chemical energy. Its action depends upon the effect of currents of
electricity on lead plates in a bath of sulphuric acid. The passage
of the current through the battery produces chemical changes which
enable the battery to give out current when required. As the battery
may remain 'charged' for several days, and may be discharged slowly
or quickly, it provides a means of 'storing' electrical energy. In
practice, and under favourable conditions, the efficiency of the
storage battery is about 80 per cent. That is to say, there is a loss
of about 20 per cent. in the process of conversion and re-conversion.

[Illustration: Fig. 8. A modern electric automobile.--The electric
battery is placed under the front half of the car, and the motors
drive the back axle through chains. (British Electric Automobile Co.,
Ltd.)]

Great hopes were once entertained of accumulator traction on tramways.
The storage battery offered a means of escape from all the difficulty
and expense of carrying electric mains overhead or underground.
By fitting each car with a storage battery, it could be made an
independent self-contained locomotive, capable of running a certain
number of miles until the battery was approaching exhaustion. By
providing centres where the batteries could be re-charged--or, to save
time, replaced by batteries previously charged--a continuous service
could be maintained on a tramway system.

The advantages of accumulator traction, apart from the saving in
first cost, are the absence of obstruction and danger from overhead
wires, and of the risk of a general stoppage of the service when the
current at the generating station fails from any accidental cause.
When accumulators are used, the conversion of a horse tramway to an
electric tramway becomes a very simple matter. All that is required
is to erect a generating station and provide each car with a storage
battery and electrical equipment. This equipment, it may be mentioned,
is substantially the same as with ordinary electric cars. The current
flows from the accumulator through the controller and the motors back
to the accumulator.

Many trials were made with this system in the early days of electric
traction, but there are no survivals. The failures were due in part to
weaknesses in the batteries and to the difficulty of handling them with
proper care under the rough and ready conditions of tramway service.
The main cause, however, was the inherent drawback of all locomotive
systems--the fact that the tractor has to haul its own dead weight in
addition to the weight of the car and passengers. Lead being one of
the heaviest of metals, this dead weight was a very serious item on
accumulator tramcars. It proved to be a fatal item when the attempt
was made to run large cars on heavy gradients. The rush of current
demanded in starting such cars up-hill was in itself too severe a tax
on the delicate structure of the batteries. In practice, moreover,
the necessity of bringing each car back to the depot for re-charging,
after a limited journey, proved very troublesome. The more extensive
the system and the more frequent the service, the more troublesome this
necessity became. Even the most enthusiastic advocate of the storage
battery was at last forced to admit that it was not applicable to a
system of transport, which demanded comparatively high speeds with
large cars on all gradients and over a range of several miles from the
centre of power.

After the admitted failure of accumulator tramways, the storage
battery was for some time used only on river launches and small
private vehicles. The conditions in both cases--and especially in the
former--are very favourable to its operation. On a river launch the
weight of the battery is not a serious item, as it serves to some
extent in the place of ballast. Launches, moreover, are generally
required for trips of a limited number of miles up and down the river
from the boathouse or charging station of the owner. In contrast with
the tramway, there is no demand for rapid acceleration at starting
or for abnormal power at intervals. The batteries discharge slowly
and fairly evenly, and are not subjected to serious vibration. The
electrical equipment is extremely simple, as the motor is fixed on to
the propeller shaft and operated by a controller on the deck close to
the steering wheel.

However, if economy were the only consideration, it is doubtful whether
the electric launch would have survived against the competition of
steam and petrol launches. It has survived because the simplicity of
the equipment, its silent running, and the absence of heat, smoke and
fumes, make it the ideal thing for river work. The hire of an electric
launch on the Thames costs more than that of a steam launch, but
plenty of people are willing to pay the additional charge to avoid the
drawbacks of steam propulsion on a small vessel.

Similar considerations underlie the extensive use of electric
broughams in cities. Such vehicles are required only for travel within
a restricted area and on streets where the gradients are seldom
severe. Their carrying capacity is generally limited to two or four
passengers, so that the batteries do not require to be unduly heavy. A
maximum speed of 12 miles an hour is quite sufficient for city streets;
and with careful treatment the batteries can be very economically
used and will not deteriorate nearly so rapidly as they would under
tramway conditions. Considerations of economy, on the other hand,
do not weigh very heavily with the class of people who use private
electric broughams. They are prepared to pay for the best available;
and the electric brougham, with its noiselessness, its easy running,
its absence of smell or other nuisance, is regarded as the ideal which
other modes of city transport must do their best to approach.

In London a certain amount of business has been done for some years
in hiring electric broughams for various periods on terms which
include current, maintenance, garage facilities, driver's wages, and
all other charges. The convenience of such an arrangement to the
hirer need not be emphasised, since what is wanted in this case is a
vehicle which is always ready at a telephone call. But the system has
another important advantage, which bears upon the economic prospects
of accumulator traction. By retaining the vehicles under its control
the hiring company not only centralises the arrangements for storing
and re-charging, but it is able to take care that the batteries are
properly treated. Just as the success of the surface-contact system
depends on minutiae of design, so the success of accumulator traction
depends upon minutiae of treatment. Carelessness in driving the
vehicles and in handling the batteries at the garage may transform
a perfectly satisfactory mode of city transport into an extravagant
nuisance. Consequently the success of this class of business depends
upon an organisation which permits of constant supervision over every
vehicle and every driver.

A good deal of ingenuity has been exercised upon the electrical
equipment of broughams; and it is probable that further improvements
will be made. In some cases the front axle is driven by the motor; in
some cases the back axle. The earliest cars used toothed-wheel gearing
in order to reduce the speed of the small fast-running motor. Improved
types on this principle still exist, but there are some interesting
forms in which the motors are placed right at the hub of the wheels and
effect speed reduction and control by electrical means, without any
intermediate gearing.

In addition to these improvements, the storage battery itself has made
a distinct advance in design and construction. It is more efficient,
more durable, and more reliable now than ever it was before. The closer
attention given to its treatment tends in the same direction; and
the result is that storage-battery makers and engineers have a very
accurate knowledge of what the accumulator will do at a certain cost
under certain conditions. The conditions being the variable factors
in the problem, and being in large measure determinable by choice, it
is rather remarkable that the engineers and financiers should have
selected, at the outset, the very conditions which were least suited to
the peculiarities of the accumulator.

The attempt to adapt battery traction to tramway work is a conspicuous
case in point, but it is not perhaps so conspicuous in the public
memory as the efforts to organise electric cab and electric omnibus
services in London and elsewhere. These efforts have been made so often
and failed so regularly that they have made it difficult to obtain
capital for any form of electric battery propulsion.

The electric omnibus has many of the drawbacks of the storage-battery
tramcar, but they are not so serious in the case of an urban service,
adequately met by small cars running at moderate speeds on short routes
with moderate gradients. It is possible that if recent metropolitan
electric omnibus enterprises had been as happy in their finance as in
their engineering, they would have succeeded well enough. But even in
their engineering they had to meet great difficulties. They sought to
protect themselves against excessive costs by entering into maintenance
agreements with the makers of the batteries; and although the terms of
these agreements were satisfactory enough, their validity depended on
careful treatment of the batteries by the drivers of the cars--a matter
which it is rather difficult to guarantee. Moreover, the number of
omnibuses put on the road was so small that the garage costs and other
standing charges were proportionally very heavy. With a larger fleet
and with efficient organisation, much better results might have been
achieved in spite of the inherent difficulties of the situation.

Although the electric cab has the advantage of being a smaller
vehicle and therefore more adapted to economical propulsion by
storage batteries, the conditions of the cab service are not at all
favourable to the system. The essential feature of a cab is that it
should be available anywhere, to go anywhere at a moment's notice. An
accumulator-driven vehicle, on the other hand, is tied by an invisible
cord to the charging station. Even if charging stations were multiplied
enormously, the electric cab would have no real freedom of action,
since several hours are required for the process of re-charging. We
have only to compare the limitations of the electric cab with the
freedom of the petrol cab (which can renew its supply of petrol in a
minute or two at any motor depot) to realise that the roving commission
is not at all suited to the former.

In 1899 a very bold effort was made to establish an electric cab
service in London. To inaugurate the service a procession of the cabs
was formed, but it excited more ridicule than serious interest. The
clumsy appearance of the cabs was against them; and their behaviour
was not satisfactory enough--as to speed and reliability--to overcome
the first unfavourable impressions. They soon disappeared, to add
another failure to the long list of disappointments in connection with
accumulator traction.

The private electric automobile remains, however, because it has been
organised under conditions which suit the peculiarities of the storage
battery. Its survival, in conjunction with the failure of a similar
means of transit for tramway, omnibus, and public cab services, has
pointed to another direction in which the electric automobile should
be a commercial possibility. That is, in connection with the local
distribution of goods from large stores and other centres.

The United States have given a very distinct lead in this matter. In
New York, Chicago, Washington, and other large cities the electric
automobile for private use is highly developed and there is also an
extensive service of electric vehicles ranging in size from a small
parcels van to a large lorry capable of carrying loads up to several
tons. No doubt the local cost of other means of transport has something
to do with this American development, which has, moreover, been
strongly supported by the companies which supply electricity to the
public. But the fundamental reason lies in the special character of the
service demanded.

The vans belonging to a large store all start from a certain point
and return to it after journeys of limited range. Owing to the period
occupied in loading up, and also to the pre-determined hours of most
of the deliveries, there is no difficulty about affording the time
required for re-charging the batteries, or in arranging each journey
so that the vehicle returns before the batteries are exhausted. With a
standardised fleet of vehicles, it is possible to remove the discharged
batteries and replace them with charged ones in a few minutes. The
whole arrangement, in fact, is like a private automobile garage, with
the advantage that the probable demand can be forecast with a somewhat
greater degree of certainty.

Steam and petrol-driven wagons run most economically on long steady
journeys at fairly high speeds, and the electric automobile does not
attempt to compete with them on these lines. But it offers competition
within city limits for door-to-door delivery; and its prospects are
particularly good for light parcel service, where the horse is still
maintaining its position against the petrol vehicle. The advantages
of the electric vehicle in neatness and noiselessness will certainly
secure its success if the cost can be proved to be not appreciably
greater than that of its rivals.

Apart from the necessity of careful organisation, the main essential
of success in electric automobile work is a supply of cheap
electricity. Owners of private electric launches have to pay anything
from 8_d._ to 2_s._ 6_d._ per unit for re-charging their batteries, but
these high prices are due to the intermittent character of the demand
and also (in some cases) to the cost of providing machinery to supply
current at special pressures for particular launches. An electric
automobile garage, situated close to a public generating station and
offering a larger and more regular demand, will of course obtain
current much cheaper. And it is possible that arrangements may be made
for supplying electricity to automobiles at a much lower rate even than
that customary for general power demands. In the metropolitan borough
of Marylebone, for instance, an electric garage may obtain current
during the small hours of the night at 1/2_d._ per unit, which is half
the standard rate for power purposes. This low price is offered because
there is otherwise practically no demand at all for electricity during
these hours. If, therefore, a garage arranges--and the arrangement is
quite feasible--to charge its batteries overnight, the power bill may
be divided by two.

The electric automobile has been used to some extent as a touring car,
but although journeys up to 100 miles have been performed on a single
charge, the time occupied in re-charging, and the difficulty of finding
convenient charging stations, are fatal to any development in this
field.

CHAPTER XI

PETROL-ELECTRIC VEHICLES AND MAIN MARINE PROPULSION BY ELECTRICITY

Between the petrol-driven vehicle and the electric automobile there is
an interesting series of links provided by 'petrol-electric' systems.

At one end of the chain, electricity plays an important part in
supplying power to drive the car. At the other end, electrical
apparatus is introduced merely as a form of transmission gear between
the petrol engine and the driving axle. The reason for attempting
the petrol-electric combination will be most readily understood by
considering the latter arrangement first.

The petrol engine is a high-speed engine, capable of working most
satisfactorily when it runs at a uniform rate with a constant load.
On the other hand, the speed of the driving axle of a car varies from
a very much lower speed down to zero. It is therefore necessary, when
driving a vehicle with a petrol engine, to arrange some forms of
variable speed-reducing transmission gear between the engine and the
driving axle. The problem is further complicated by the fact that the
petrol engine is irreversible, has practically no 'starting torque,'
and has a very slight overload capacity. It has to be started running
'light' and then switched on to a low gear which gives sufficient power
to overcome the inertia of the car. As the speed of the car rises,
there have to be successive changes of gear. These difficulties are, of
course, accentuated when dealing with the heavy weight of an omnibus.

[Illustration: Fig. 9. Elevation and plan of a petrol-electric motor
omnibus equipped by W. A. Stevens, Ltd. Directly behind the front
wheels is the petrol engine, driving a dynamo through a flexible
coupling. The dynamo supplies current to the motor directly behind
it; and the motor drives the rear wheels through a cardan shaft. The
transmission of power between the engine and the shaft is electrical
at all speeds.]

Practically all the troubles with petrol motor omnibuses have resided
in the gear; and even the most ardent enthusiast for the all-electric
faith must admit that the motor engineer has overcome these troubles
(in great part if not wholly) with remarkable skill and ingenuity.
But the complications of an adjustable mechanical bridge between a
high-speed engine and a varying low-speed axle are so great that
an electrical bridge was proposed as a substitute. By coupling the
engine direct to a dynamo and by using the current so generated to
drive variable-speed motors geared to the driving axle, the electrical
engineer hoped to get better working results from the petrol motor than
could be obtained with any mechanical transmission gear.

The most conspicuous advantage, apart from the quietness of running
at all speeds, lies in the ease and smoothness with which the
petrol-electric motor can start and gain speed. In this respect the
combination system is practically on the same level as (or even
superior to) the electric tramcar or the electric automobile. There
is an entire absence of the jerks and jarring noises which usually
accompany the starting of a motor omnibus. The same facility of control
is of advantage in adjusting speed to suit the other traffic on the
road, and also in negotiating hills.

In one class of petrol-electric vehicles the electric transmission gear
is continuously used. In another, it is used at all speeds except the
highest, when the engine is coupled directly (by a magnetic clutch)
to a mechanical driving gear. In a third class the arrangement is
more complicated, as it involves the use of storage batteries as an
auxiliary to the power provided directly by the petrol engine. The
Fischer type of petrol-electric vehicle uses electric transmission
solely and has a fairly large battery to supplement the engine-produced
current when steep hills are being negotiated. At ordinary speeds on
level roads the surplus power produced by the engine goes to charge the
battery.

The 'Automixte' type is peculiar in using the mechanical transmission
gear all the time. The dynamo coupled to the engine supplies current to
a small battery when surplus power is available; the same dynamo may
be driven as a motor by current from the battery when such assistance
is wanted at starting or on steep hills. The electric part of the
equipment thus acts first as a generator and then as a motor, the
change taking place automatically.

These different petrol-electric devices are very attractive from the
engineering point of view, but at the present time it is uncertain
whether they will realise the hopes of their inventors. The additional
weight of the electric equipment is against them; and in some cases
there appears to be a lower all-round efficiency. So that the
motor-omnibus world, as a whole, continues to fix its faith upon the
improved forms of mechanical transmission.

The underlying idea of the petrol-electric system has, however, been
suggested for marine propulsion with a somewhat better prospect of
success.

There is a partial analogy between the conditions of motor omnibus
working and of ship propulsion with turbines. The steam turbine
is, like the petrol engine, essentially a high-speed machine. The
screw propeller, on the other hand, works most efficiently at low
speeds. Therefore the marine engineer has to try and find some
common denominator between an engine which runs most efficiently
at high speeds and a propeller which is at its best when revolving
comparatively slowly.

[Illustration: Fig. 10. Diagrammatic section of a steamship which
has been 'converted' from the ordinary method of propulsion to the
'Paragon' system of electric main marine propulsion. The reciprocating
engine has been replaced by a steam turbine, coupled direct to an
electric generator which supplies current to a motor attached to the
propeller shaft. The tests carried out with this vessel will indicate
the advantages of the electric method of propulsion even with the
usual long length of shaft. The vessel has a gross tonnage of 1241,
and its speed is 9 knots. The engines replaced ran at 78 revolutions
per minute and gave 500 brake horse power. The turbine now installed
runs at 2500 r.p.m., and develops 630 brake horse power. (Illustration
reproduced by courtesy of _The Electrician_.)]

The gulf between the two has been narrowed by the improved design
of propellers. Some engineers assert that continued improvements will
bridge the gulf completely. Others have sought the solution in the
same way as the motor engineer--by the use of mechanical change-speed
gears. The suggestion has also been made to employ hydraulic gear as
an intermediary; and in some recent vessels reciprocating engines with
comparatively low-speed turbines driven by exhaust steam have been
adopted.

In the electric system the turbine is coupled direct to an electric
generator and may run continuously at the highest economical speed.
The propeller shaft may be quite short and is driven by a slow speed
motor connected by cables to the generator. Various arrangements for
controlling the supply of current to the motor (with appropriate
design of generator and motor) have been devised by Mr Durtnall, Mr
Mavor, and other workers in this field; but whatever the details of
these arrangements may be, they all give a wide range of speed both
ahead and astern. The direct drive with the steam turbine has really
only one speed--full speed ahead; and as the turbine is irreversible,
'astern' turbines have to be installed in addition. These limitations
and complications are removed entirely when electrical transmission is
adopted.

Moreover, the electric system can be so arranged that the control gear
may be operated from the bridge itself. The facility in manoeuvring is,
in fact, so marked that it would recommend electric marine propulsion
even if that system offered no advantages on the score of economy
in weight, space, and steam consumption over the existing systems.
The steam turbine, it may be noted, has been adopted so far only in
high-speed vessels; and it is generally recognised that its extension
to vessels which run at 12 or 16 knots depends upon its adaptation to
slow-speed propellers. Advocates of electric marine propulsion claim
that they hold the most efficient solution of this problem.

It may also be pointed out that a considerable section of marine
engineers look forward to the use of internal combustion engines
(driven by oil or gas) on board ship. For naval purposes especially
it would be a great advantage to do away with funnels and so leave
the decks more free for gun mountings. As internal combustion engines
are irreversible, the electric system offers a means of escape from a
fundamental drawback to their use at sea. Here again the perfection of
manoeuvring power, especially with twin screws (either of which may
be controlled from the bridge through a wide range of speed ahead or
astern), gives the electric system a strong claim for consideration by
the naval authorities.

It is hardly necessary, except as a matter of curiosity, to refer to
the suggestions made, from time to time, of accumulator-driven ocean
steamships. Some wonderful pictures have been published of large
vessels with tons of ballast in the form of storage batteries. They are
likely to remain in this ideal condition, for although the driving of a
large vessel by stored electricity is quite possible, it is also about
the most expensive method which has ever been proposed.

Electric power from storage batteries has been used as an auxiliary
in the propulsion and manoeuvring of submarines. In aerial navigation
electricity has so far been employed to a very limited extent. Small
airships have been designed to carry electric accumulators connected
with various motor-driven propellers for raising, lowering, going
ahead or astern, and steering. The switches which control the passage
of the current to these propellers are connected with a wireless
telegraph receiver, so that each operation may be started or stopped
by a particular ether wave or series of waves. Demonstrations of such
'wireless-controlled' airships have been given in theatres; their
field of usefulness, if any, is in connection with war on land or sea.
Whether they will have any better fate than other devices for dropping
bombs over the enemy's camps or ships remains to be seen.

One inventor has, I believe, suggested a means of direct electrical
propulsion for aeroplanes, the current being derived from a
petrol-driven generator and carried to motors attached to propellers so
arranged as to give certain advantages in stability and manoeuvring.
As yet, however, the probability of electricity being applied to
locomotion in the air as well as on land and on sea is somewhat remote.

CHAPTER XII

THE PIONEER ELECTRIC RAILWAYS

Electric tramways have reached a period of middle age in which they
are more concerned about their internal economy than the prospect of
enterprise in new directions. Such development as they feel capable
of making under present legislative conditions is only by proxy and
tentatively, with the aid of the trolley omnibus.

Electric railways, however, have still many worlds to conquer. They
are now in much the same position as electric tramways held about the
year 1896. That is to say, they have already given practical proof of
their capabilities and enabled engineers to point out the directions
along which they are certain to develop. In the railway world there
is a growing conviction that the adoption of electric traction on all
suburban and inter-urban railways must be simply a matter of time. For
main line traffic the possibilities of using electricity are as yet
only an article of faith among electrical engineers.

Although the earliest experiments in electric traction were made in
the railway form, the first electric lines could hardly be regarded
as railways in the ordinary sense. They were really light railways,
in which the traffic conditions approximated to those of tramways.
The routes were short, the cars small, and the traffic of modest
dimensions. They contained the germ of both the tramway and the
railway; but, in the case of the railway, many years of technical
development had to pass before the problem of applying electricity
to the handling of large masses of traffic under standard railway
conditions was solved.

The fact that the first electric railway in the United Kingdom was
constructed at the Giant's Causeway (in 1883) is significant. The
Giant's Causeway is one of the few places in our islands where water
power is available close to a district with a demand for traffic
facilities. In 1885 another electric railway deriving its energy from
water-driven turbines was built between Bessbrook and Newry. At that
period it was considered that waterfalls provided the only really
feasible source of cheap electricity on a large scale. Even yet the
impression survives that electric power stations using steam cannot
produce current so cheaply as those which 'harness' waterfalls. Many
people, in fact, are inclined to attribute the comparative backwardness
of electrical development in Great Britain, not to legislative
conditions, but to the lack of large waterfalls.

There might have been more active progress in the pioneering days
if the presence of water power at convenient points had encouraged
electrical engineers to repeat the experiments at Portrush and
Bessbrook. But at an early stage in electrical history it became clear
to engineers that coal was just as feasible a source of cheap power
as water. The idea that a waterfall provides power 'for nothing'
is one of those superficial conceptions which make the hardiest of
fallacies. To 'harness' a waterfall requires a heavy expenditure of
capital on conduits, pipe-lines, dams, and other works. The interest
upon that capital is a heavy item, apart from the cost of maintenance
and repairs. Waterfalls are situated in mountainous country, generally
remote from the centres of industry; the water-power station,
therefore, has to face the cost of transmission mains and the loss
of energy involved in conveying the power to the place where it is
wanted. Further, waterfalls and the adjacent ground belong either to
individuals or to the State; and payment is generally exacted for the
right to use them.

All these items have to be covered in the price charged for current to
the public or to railway undertakings. Nature may provide the 'head' of
water 'free,' but man has to spend money in utilising it, just as he
has to do in mining and in obtaining heat from the coal which is also
provided 'free.' Anything which is obtained 'for nothing' is generally
worth nothing.

The full economies of generating electricity by steam power are
not, however, realised until business is done on a large scale. As
the first essential of a successful electric railway is a plentiful
supply of cheap power, development from the experimental stage of
Portrush had to wait until engineers mastered the art of producing
electricity from large generators. They gained the necessary experience
with electric tramways and in electric lighting. We have seen how,
as regards tramways, legislation delayed and hampered progress. A
similar cause was at work in connection with electric lighting. In
1882 an Act was passed regulating electric lighting on lines modelled
upon the principles of the Tramways Act, 1870. Capitalists declined
to work under this Act; and it was not until after 1888, when the
Act was amended, that any money could be found in Great Britain for
electric lighting schemes. This delay was a serious handicap not
only to electric lighting but to the business of British electrical
manufacturing, as there was, comparatively speaking, no demand for
electrical plant for over six years. Meanwhile, matters had been
advancing on normal lines in other countries; and when the demand came
at last, the manufacturers on the Continent and in America were the
only ones organised and ready to meet it.

These points must be touched upon in order to understand why so long
a period elapsed between the pioneer electric railways and the real
electric railway movement as we know it to-day. They also serve to
explain the prominent part which American and German firms took in
electrical developments here. Engineering and legislative conditions
combined to retard electric railway enterprise so that it did not begin
to take firm root in Great Britain until about 1890, and did not attain
to any conspicuous growth until the beginning of the twentieth century.

Until after 1890 the only electric railways in Great Britain taking
power from steam dynamos were those at Brighton Beach, Ryde Pier
(Isle of Wight) and Southend Pier, opened in 1883, 1886 and 1890
respectively. These were all, of course, of short length. The Brighton
Beach railway, designed and constructed by Mr Magnus Volk, was a unique
piece of work. The rails were laid on heavy concrete blocks below
high-water mark; and the cars were platforms raised on a light iron
structure. Power was conveyed to the cars from wires hung on posts like
the standards of a tramway on the trolley system. The unusual sensation
of travelling over the water was enjoyed by hundreds of people until
the difficulty of maintaining the track (owing to the erosive action of
the waves) led to the railway being abandoned and another line of more
ordinary character being laid on the level of the undercliff roadway.

The first indication of the genuine electric railway movement was given
in 1893, when the Liverpool Overhead Railway was opened. This line was
constructed to afford communication along the line of docks fringing
the Mersey. The track was carried on a continuous bridge in order to
avoid obstruction between the docks and the streets behind; and being
overhead, there were serious disadvantages attached to the use of steam
locomotives. Electric locomotives were therefore employed.

In this case, it should be noted, electricity was not adopted because
it was more economical or efficient than steam. The reason lay with
the peculiar situation of the railway. A similar reason decided
the promoters of the City and South London Railway to try electric
locomotives on their line. This railway, which was opened in 1890, was
the first deep level or 'tube' railway in the world. Moreover, it was
constructed and equipped throughout by British engineers, and at a time
when the art of tunnelling was much less advanced than it is now. In
the later and more imposing development of tube railways in London,
the foresight and enterprise displayed by the pioneers of the City and
South London Railway are apt to be overlooked. It was, however, the
success of the original line from the Monument to Clapham which made
it possible to raise capital for the Central London Railway (opened
in 1900) and for the extensive tube railway system organised by the
Underground Electric Railways Company of London.

On a deep-level railway, steam is, of course, out of the question. Even
on the old 'Underground,' built close to the surface and furnished with
frequent openings at the stations, and by means of ventilating shafts,
the atmospheric conditions were abominable. The sulphurous fumes were
indeed recommended for asthma and other complaints, but on a tube
railway they would have been sufficient to cure every human ailment.
Therefore the choice lay between electric traction and haulage by
cables, compressed air, or some other innocuous system. Within these
limits electricity was chosen on its merits.

The first railway in Great Britain to undertake conversion was one
in which both the physical and economic troubles were exceptionally
serious. The Mersey Railway is little more than a tunnel under the
river, and it is distinguished by heavy gradients and by the continuous
necessity of pumping out the water which drains into it. With steam
traction the difficulty of ventilating the tunnel was an added trouble.
Owing to these various causes the working expenses were abnormally
heavy, and led ultimately to a receivership. Electric traction was
adopted as the only possible cure. The pumping and ventilation
arrangements were both reorganised for electric power; and the trains
were equipped with electric traction on the 'multiple-unit' system, an
arrangement--to be described in the next chapter--which is well suited
to the economical handling of steep gradients. The practical result was
a great increase in traffic, with a marked decrease in the proportion
of expenses to receipts.

No other British railways, happily, were in so desperate a condition
as the Mersey line, but all of them were, at the end of last century,
feeling the effect of certain disquieting tendencies. These tendencies
were most marked in connection with suburban and short-distance
inter-urban traffic, which is quite distinct in character from the
main-line traffic. We talk glibly enough of railway traffic as if
it were a unity, but it is clear that very different considerations
govern the traffic on a main line between, say, London and Glasgow,
and those which control the traffic on London suburban routes or on a
railway connecting the adjacent towns of the Potteries. Some railways
have to deal with all three classes at the same time and occasionally
on the same lines of rails. Electric traction has, so far, made itself
felt only where the suburban or similar inter-urban traffic has been
separable from the main line traffic.

The growth which took place in suburban traffic before and after
the end of the century ought to have brought increased prosperity
to the railway companies, but it did not always do so. Competition
between the various companies led to a reduction in fares; Parliament,
by establishing workmen's fares, forced the companies to carry an
ever-increasing number of passengers at a loss, or at least without
profit; wages tended to increase and hours of working to decrease--both
affecting the cost of operation; rates and taxes became heavier and
heavier with the growth of municipal expenditure; and a higher standard
of comfort and efficiency was demanded by the public. In some instances
the situation was aggravated by the competition of electric tramways
along routes parallel to the railways. This competition was limited to
point-to-point traffic, its maximum range being about three miles; but
it was a grievance against which the railway companies protested very
loudly, especially when the tramways were owned by local authorities to
which the railways paid large sums in rates.

The general effect of all these factors was to reduce the margin of
profit on which the railways were working. We have seen, in the case of
tramways, how easy it is for a slight change in a frequently-recurring
expense to have a serious effect in the aggregate. Railways are in
much the same position; and the various influences at work upon the
suburban traffic brought them face to face with the importance, if not
the necessity, of finding some means of dealing with larger volumes
of traffic on a basis more economical than that provided by steam
locomotives.

This means they found in electric traction; but it may be noted that
even railway engineers took some time to realise exactly what electric
traction offered them. They were looking for something to reduce
their annual expenses; and when they made calculations about electric
traction they found that, when the expense of providing the electrical
equipment was taken into account, the total cost of hauling the trains
electrically on the existing schedule might be greater instead of less
than the cost of steam haulage. They were therefore inclined to look
upon the economic benefits of electric traction as an illusion.

In course of time, however, it came to be recognised that the function
of electricity is not to act like a blue pencil on the debit side of
the revenue account. Its essential purpose is to increase the volume of
traffic. From the public point of view this is very much more valuable.
Passengers are not directly concerned with means of reducing working
expenses, but they are closely interested in the improvement of the
frequency and speed of the service. The adoption of electricity on
suburban lines has really been dictated by the demand for increased
facilities. At the 'rush' hours of the morning and evening, when
the great tide of workers flows and ebbs, the capacity of the steam
lines was taxed to the utmost. And with the growth of population the
difficulty of running sufficiently frequent trains became almost
insuperable.

Apart from these particular necessities, the general features of
railway economics point to the supreme advantage of increasing the
volume of traffic in every possible way. In a railway, as in a tramway,
the preponderating item is the cost of construction and maintenance;
and unless a certain minimum of traffic is carried, the most economical
working in the world will not secure a profit. The standing charges
fall upon the idle hours as well as upon the busy; for every minute
that a line of rails stands empty there is a loss of money. Railway
progress depends upon reducing the proportion of idle hours; and that
can only be done where there is scope for the growth of traffic, and
where there is means--such as electric traction--of dealing with that
growth on an economical basis.

In the succeeding chapter it is explained how electric traction
enables a more frequent service to be run with advantage even on
systems which were worked to the maximum limit possible under steam
conditions. But in the meantime it will be interesting to trace the
effect itself on a railway which soon followed the Mersey Railway in
making the change from steam to electricity--the Metropolitan District
Railway.

[Illustration: Fig. 11. An electric train on the Metropolitan District
Railway, equipped by the British Thomson Houston Company. The front
and rear cars and one intermediate car are equipped with electric
motors, all controlled from the 'cab' at the end of the train. The
controller handle may be seen close to the nearest window of the first
car. The rail immediately in front of the foot of the guard is the
conductor rail which conveys the current to the train. The rail
between the track rails carries the return current.]

Throughout the steam age the finance of the District Railway Company
was as unattractive as the physical conditions of the railway itself.
No dividend was ever paid on the ordinary shares; and even with the
growth of London there was little prospect of any dividend ever being
paid. When--about ten years ago--the late Mr C. T. Yerkes came over
from America and obtained a controlling interest in the District
Railway Company with a view to converting it to electric traction, he
was regarded as a philanthropic enthusiast. Many of the shareholders
themselves were reluctant to give their assent to the change; they
preferred to bear the ills they knew than fly to others which might be
introduced by an American financier.

But Mr Yerkes and those who worked with him had something more in
view than the improvement of traffic on the District Railway. They
acquired control of several tube railway schemes and obtained powers
for new lines, so as to organise a comprehensive system of underground
electric transport in London. They had sufficient faith in the traffic
possibilities of London to find the enormous capital required to
construct these tube railways and also to convert the whole District
Railway to electric traction. The constructional work occupied several
years; and after the lines were opened one by one, arrangements had to
be developed for through-bookings among the various lines and between
them all and the existing underground railways like the Central London
Railway, the Metropolitan Railway (closely linked with the Metropolitan
District) and the City and South London Railway. A systematic attempt
was also made to develop the travelling habit in London by persistent
advertising of the railway services and by increasing the frequency
and rapidity of the trains. From these points of view the organisation
of the network of lines comprehensively known by the title of
'Underground' is certainly unsurpassed.

The difficulties which had to be overcome in this great work were
enormous, but there has been no break in the thread of progress.
The 'tubes' are paying dividends which, though modest, are an
encouragement to further developments. The finance of the District
Railway has lost its element of chronic despair. Considered as a
whole, the results prove that where there is the potentiality of large
traffic, electricity is the instrument which must be applied. During
the steam days, the most crowded part of the District Railway (the
'Inner Circle') carried a maximum of 16 trains per hour. With electric
traction that figure has been raised to 40 trains per hour. And the
remarkable thing is that with each increase in the service the traffic
grows. Many people welcomed the electrification of the District as a
measure of relief from the overcrowding on the steam trains during the
busy hours. But with a service of trains more than doubled in frequency
and also increased in capacity per train, overcrowding continues and
the 'straphanger' has become an established institution.

It may be accepted as substantially proved that, on suburban and
inter-urban railways in populous districts, electric traction is a
means of increasing traffic and diminishing the proportion of working
costs. Moreover, these results have been achieved in conjunction with
substantial reductions in fares and with marked improvements in the
comfort of travelling.

The engineering aspect of these changes has now to be considered.

CHAPTER XIII

ELECTRIC RAILWAYS FROM THE ENGINEERING POINT OF VIEW

When electric railways were first considered, the natural tendency
of engineers was to follow the existing model and merely substitute
electric locomotives for steam locomotives. In point of fact, however,
the engineering method now adopted is an evolution from the tramway
model, not from that of the typical railway.

A certain advantage was, of course, to be gained by replacing steam
locomotives by electric ones. The greater 'starting torque' of the
electric locomotive enables it to get a train up to full speed more
quickly; and the capacity of the electric motor for taking heavy
overloads assists the electric train in surmounting heavy gradients.
Some advantage was also gained by producing all the power at a central
source, instead of having a large number of steam locomotives, which
are really power stations on wheels. But the electric locomotive had
still to be made heavy enough to get sufficient grip of the rails;
it had to haul its own dead weight; and it had to be made powerful
enough to tackle a full-sized train on the steepest gradient with its
complement of passengers, although the general demand upon it might be
considerably less than that maximum.

The electric locomotive, in short, was an advance upon the steam
locomotive, but it did not get past the essential drawbacks of the
locomotive system. A locomotive is most economical when hauling full
trains for long distances at a uniform speed; it is essentially a
long-distance machine. The first demand for electrification came,
however, from suburban railways, where the stations are close together
and where, therefore, the speed is constantly varying from zero up to
a maximum and back to zero again. The traffic also fluctuates between
extreme limits; and there is obvious waste in having to run heavy
locomotives and trains backwards and forwards during the slack hours.
There was therefore a demand for some method of propulsion which would
enable the length of trains and the consumption of power to be adjusted
more closely to the variations in the traffic.

A step in the right direction was taken when the locomotive equipment
was placed on a car, thus utilising the weight of the passengers to
increase the adhesion on the rails. But the full advantages of electric
traction were not realised until what is known as the 'multiple-unit'
system was adopted.

The idea underlying this system is quite simple. If, instead of
concentrating the motive power on a single locomotive or driving
unit, we distribute it among the cars forming a train, we get the
multiple-unit system. An electric tramcar and a trailer attached
to another tramcar and trailer, with a third tramcar behind, would
form a model for a multiple-unit train. By connecting the electrical
equipments on the three tramcars--front, middle, and rear--it would be
possible to control the train from either end or from the middle.

This is the principle upon which all the electric railways in Great
Britain are now worked, with the exception of the City and South London
Railway, where locomotives are still used and where the trains are
comparatively short and light.

It will be seen that each multiple-unit train is readily divisible. A
single motor car may be run, or a car with one or two trailers, or a
long train made up of as many motor cars and trailers as the platforms
will accommodate. And whether the trains are long or short, the power
absorbed is in proportion to the length of the train and the load of
passengers. By this simple means power is economised, and the railway
engineer is able to reduce the proportion of idle rolling stock.

The adjustment of the length of trains to the fluctuations of the
service is made easier by the absence, in the multiple-unit system,
of the necessity of shunting at the termini. As a multiple-unit train
can be controlled from either end, a more frequent as well as a more
flexible service can be run. With steam traction the number of trains
which may enter or leave a terminus is limited by the time occupied in
shunting and by the necessity of leaving lines of rails free for that
operation. With an electric train on the multiple-unit system, no more
time is lost than the few seconds necessary for the driver to walk from
the front of the train to the rear, which then becomes the 'front.'
No lines have to be kept open for shunting locomotives, so that the
available accommodation for trains is considerably increased. Some of
the London railway companies have spent enormous sums in enlarging
their terminal accommodation and have found that it is still inadequate
to the demands of the 'rush' traffic. Electric traction therefore
offers them an improvement of enormous value without the expenditure of
a penny on station alterations.

The crowning advantage of electric traction lies, however, in the more
rapid acceleration which it affords. We have already seen how important
this item is on tramways. It is still more important on suburban
railways, where a high average speed, in spite of frequent stops, is a
vital matter.

On the District Railway the rate of acceleration in the old steam
days was about 6 inches per second per second. It was, in fact, so
low that the trains could not reach a fair speed before the brakes
had to be applied to bring the train to a stop at the next station.
With electric traction the rate of acceleration has risen to about
18 inches per second per second. On the Liverpool Overhead Railway a
rate of 36 inches per second per second was reached in certain tests.
Heavy starting currents are, of course, necessary to bring a train from
rest to full speed at such a rapid rate, but it is quite possible for
the electrical engineer, without being unduly extravagant in current,
to accelerate a train more quickly than the passengers would find
comfortable.

The practical result of rapid acceleration (combined with rapid
braking) is not only to give a higher average speed but also to enable
a more frequent service to be run. Owing to the block system on
railways it is impossible for trains to follow each other closely in
the manner of tramcars; and it is therefore of cardinal importance that
no train should occupy a block for one second more than is necessary.
Rapid acceleration becomes all the more important in this respect
because of the difficulty of setting down and picking up passengers
quickly. This difficulty is overcome in part by using saloon carriages
with middle and end doors, in place of compartment carriages. At first
the District Railway tried to help matters by operating these doors
pneumatically, but the mechanism became unpopular after a number of
late-comers had been pinched by closing doors. The management has
reverted to hand operation; and it has probably achieved more by
educating the public to move quickly than it would have gained with its
too-perfect mechanical system.

London travellers have become so accustomed to entering and leaving
trains quickly that it is possible for an observer to distinguish
strangers by their slower movements on an underground railway. Thus
the passenger, as well as the service, has been 'speeded-up.' The more
frequent service of trains with a higher average speed would not have
been possible, however, without an improvement upon the old methods of
signalling. There is no need to dwell upon the weakness of the human
element in railway signalling; and it will be clear even to the layman
that the strain of handling traffic with a headway of one minute and a
half, or less, would be more than men could stand. Automatic signalling
had therefore to be adopted to obviate the risk of disaster.

Each train, as it leaves a block or section, 'clears' the signals
for that block; and when any train attempts to enter a block against
signals, the current is automatically switched off and the brakes
applied. The system is so perfect that, in spite of the enormous
traffic worked under it, there has been no failure and no accident.
It is, of course, costly to install; and its cost can be justified
(financially) only when the traffic is very heavy--that is to say, when
the conditions make it almost a necessity.

The supply of electric power to electric railways is organised on
practically the same lines as in the case of tramways. That is to say,
current is generated at a central station, transmitted at high pressure
to various sub-stations, and supplied from there at working pressure
through 'feeders' to each section of the system. In the case of the
'Underground' system, most of the power is taken from a single huge
electric station at Chelsea. Current from that station drives trains as
far west as Wimbledon, Hounslow, and Ealing, as far north as Highgate
and Golder's Green, and as far east as Barking.

This is a magnificent example of the concentration which gives
economy. If each of the underground railways forming the system had
erected its own generating station, the total initial outlay, on
land, buildings, and machinery, would have been greater, and the
cost of current would have been higher, owing to the smaller output
and the more irregular demand which a single railway affords. The
ideal electric power station is one which is constructed with the
largest generating units and produces current at its maximum capacity
throughout the twenty-four hours of each day. The Chelsea power station
is nearer the ideal than a smaller one supplying a short railway could
be. And a station of the latter class is, it may be noted, nearer the
ideal than the arrangements on a steam railway, where the sources of
power are scattered in hundreds of locomotives.

The concentration of power is therefore one of the many factors which
have enabled electric railways to give a vastly improved service at
lower fares.

With two exceptions--to be considered in the next chapter--the electric
railways of Great Britain are constructed on the 'third-rail' system.
They are thus a reversion to--or, rather, a survival of--the original
type adopted by Siemens in 1879. The 'third-rail' is carried on
insulators a few inches outside the track rail; and the motor cars are
provided with a 'brush' or 'shoe' which slides along it and collects
the current. In the centre of the track there is generally a second
insulated rail to carry the return current, as it is more convenient,
under railway conditions, to have a conductor independent of the track
rails than to follow the tramway plan of using the rails 'bonded'
together. In stations and at crossings the third or 'live' rail is
protected by a wooden board in order to reduce the risk of shock to
anyone falling on the line or walking upon it. The board is placed high
enough over the rail to allow the shoe to pass freely.

As regards the motor equipment on the cars, tramway models have been
followed very closely. The 'series-parallel' system of control is again
adopted in order to get the high starting torque which gives rapid
acceleration with moderate current consumption. The course of the
current is again from the live rail, through the controller, through
the motors, and thence to the return rail. The controller itself is
more or less on the tramway principle; and the main modification in
it is the arrangement which enables all the motors on a multiple-unit
train to be operated by a single controller. This is done by connecting
the controllers electrically and using electric power so that they all
work in unison. Some companies use, for this purpose, compressed air
controlled by electricity instead of electric power alone, but in both
cases the principle is essentially the same.

Considered as a whole, the difference between a tramway and an electric
railway on the third-rail system is a difference in degree, not in
kind. The traffic is greater and the speeds higher, but both serve
the purposes of comparatively short-distance transit. Indeed, within
certain limits they compete with each other.

There remains to be considered another type of British electric
railway which points the way to the extension of the new mode of
traction to main line railways.

CHAPTER XIV

ELECTRIC TRACTION ON MAIN LINE RAILWAYS

On tramways, automobiles, and 'third-rail' lines, the electric current
used belongs to the type described as 'continuous' or 'direct,'
because the flow is always in the same direction. The other type
of current is known as 'alternating,' as it flows backwards and
forwards many times per second. There are several kinds of alternating
current--single-phase, two-phase, three-phase, and polyphase--each
produced from generators designed in a particular way.

It is not possible to give any adequate account of these different
kinds of alternating current without going rather deeply into the
theory of electricity. The ultimate practical point is that in
transmitting alternating currents the circuits increase in number with
the phases. Thus, three-phase current requires three wires, two-phase
current three or four wires, and single-phase current a single circuit
like that of continuous current[1].

[Illustration: Fig. 12. Photograph of a train on the electrified
section of the London, Brighton and South Coast Railway. The overhead
wire is suspended from cables stretched between insulators, and
current is conveyed from it to the trains through a 'bow' which slides
along its lower side. The photograph is taken from the rear part of
the train. The front and rear cars are both equipped with electric
motors.]

Where current has to be conveyed economically over long distances, it
is generally done in the form of alternating current at high pressure.
For instance, the transmission from a tramway power station to the
sub-stations is almost uniformly by three-phase current at, say, 5000
volts. When it reaches the sub-station, it is 'transformed' down to
the working pressure of 500 volts and 'converted' from alternating to
continuous current by means of rotary machinery. The transforming is
done by a stationary piece of apparatus similar in principle to the
familiar induction coil. An induction coil takes current at a few volts
from a battery into its primary circuit and transforms it, by induction
in the secondary circuit, into current of high enough voltage to give a
long spark. A transformer can be designed to 'step-up' or 'step-down'
the pressure according to the requirements of the case.

So much explanation is necessary to give some account of the
alternating current railways on the Continent and thence of the
single-phase system on the London, Brighton and South Coast Railway.
The Morecambe and Heysham section of the Midland Railway is also
equipped on the single-phase system.

Most of the earliest electric railways on the Continent derived
their power from waterfalls and had to transmit it for a considerable
distance. Three-phase current at high pressure being adopted for this
purpose, the Continental engineers set to work to find some means of
utilising the high-pressure three-phase current directly. They did this
by carrying the three wires on poles alongside the railway track, and
using three 'bow' collectors (in place of trolley wheels) to convey
the current to transformers on the motor cars or locomotives. In these
transformers the current was brought down to working pressure and then
led to motors designed for three-phase current.

An immense amount of technical ingenuity was exercised in developing
this system; and when the Metropolitan Railway decided to follow the
District in electrifying its lines, a three-phase system was proposed.
As the Metropolitan and Metropolitan District companies share the
working of the Inner Circle, it was necessary that both should adopt
the same system. The result was that the question between three-phase
and continuous current working had to go to arbitration. After a
long discussion of masses of technical evidence, Mr Lyttelton, the
arbitrator, decided that the direct current system was better suited to
the conditions of traffic on an underground railway in London.

The wisdom of that decision will not be questioned now. Three-phase
motors do not give the rapid acceleration which is so urgently required
on suburban lines; there are complications in speed control; and
the necessity of having three overhead conductors is also a serious
drawback. For comparatively long-distance traffic with few stops,
however, the three-phase system is quite suitable. That is to say, it
is a possible solution of the main line problem.

The great simplicity and flexibility of the power supply arrangements
in the case of alternating current traction encouraged engineers to
find something better adapted to ordinary railway conditions than the
three-phase motor. Their problem was to find an arrangement which
required one overhead conductor instead of three, and also provided
a motor with the high starting torque and easy speed control of the
continuous-current motor. After much theoretical and experimental
work, they found it in the single-phase system, using a motor which is
similar in many respects to the continuous-current motor but capable of
being operated by alternating current.

On the advice of Mr Philip Dawson, the London, Brighton and South
Coast Railway Company decided to experiment with this system on the
double line connecting London Bridge and Victoria stations, about
9 miles long. Power is supplied to each track by a single overhead
conductor carrying current at 6000 volts. Transformers are placed on
the trains to bring the pressure down to 300 volts; the current is
then led through controllers to single-phase motors in much the usual
way. The reason for using so high a pressure on the overhead line is
not only economy in transmission. If lower pressures were used, the
heavy currents required for train propulsion would require a thicker
conductor and correspondingly heavier supports. At 6000 volts it is
possible for two double sliding bows to collect sufficient current
for a heavy train from a wire which is comparable in thickness to the
ordinary trolley wire of a tramway.

The power distribution arrangements, it will be noticed, are very much
simpler than with continuous current on the third-rail system. There
are no sub-stations with rotary machinery. Power is supplied direct
from the generating station to the overhead line and is transformed
down by stationary plant on the train itself. Single-phase traction
represents, in fact, power transmission for railway purposes reduced to
its simplest elements.

The overhead construction differs, however, in some important points
from the tramway standard. The supports, which are in both bridge and
bracket form, are stronger; the insulators are, owing to the much
higher pressure employed, more massive; and a different means of
suspension has been adopted. Each conductor is hung by links from two
steel cables stretched chain-wise between the supports. This method of
'catenary suspension' enables the bow to slide along the wire without
the jolts which are noticeable with a tramway trolley. Such smooth
running keeps the bow continuously at an even pressure on the wire--an
advantage which is of great importance at high speeds. The trains are
arranged on the multiple-unit system.

The full financial results obtained on this railway have not so far
been made public; but it is sufficient for our purpose to note that
the Company, after more than a year's full trial, extended the system
to the Crystal Palace and to Croydon. Further extensions are, it
is understood, contemplated over the suburban lines to Sutton and
elsewhere; and in course of time the conversion of the main line to
Brighton will be undertaken.

Here we touch upon the most interesting aspect of this demonstration of
electric traction on the single-phase system. The system was adopted
in the first instance because the third-rail system would lead to
complications and dangers which could not be permitted at crowded
railway termini shared by all kinds of traffic, suburban and main line.
But the advisers of the Company had also in view the possibility of
development beyond the range of suburban traffic. They therefore sought
a system which, while comparable to the third-rail continuous current
in the handling of suburban business, would be adaptable to main line
conditions, where infrequent stops and long runs at high speeds are the
rule.

The adoption of electric traction on such a route as the Brighton
main line would be a benefit in several ways. It would lead to a
faster express service, as the high overload capacity of the electric
motor enables it to take small account of gradients. It would also
lead to a more frequent service, as the electric system is free from
the conditions which force a steam railway to try to concentrate
traffic on a limited number of long trains. Further, it would, by
reducing the time lost in stopping and starting, bring the average
speed of stopping trains much closer to that of express trains. All
these improvements--assisted, probably, by lower fares--should lead
to a great increase in the volume of traffic, thus reproducing the
characteristic results of electric traction on suburban lines.

[Footnote 1: An admirable explanation of alternating currents will be
found in Mr Frank Broadbent's _Chats on Electricity_. (Werner Laurie,
1910.)]

CHAPTER XV

CURIOSITIES OF ELECTRIC TRACTION

Like many other industries, electric traction has had its history
brightened and made picturesque by curiosities of invention. Locomotion
has, in fact, been a favourite field for the freak inventor; and some
of his efforts with electric cars have been as weird and as fatuous as
the most remarkable of perpetual motion devices.

One of these electrical monstrosities was, indeed, a kind of
perpetual motion arrangement. It was invented about the year 1890 and
consisted of a car equipped with accumulators which supplied power to
a motor which drove a hydraulic pump, which in turn worked a dynamo
supplying current to motors driving the axles of the car, and also to
the accumulator for re-charging purposes. The inventor was so sure that
he had got the better of the law of the conservation of energy that he
provided his car with pointed ends, fitted with revolving fans to break
down the air-pressure, in order that a speed of 125 miles per hour
might be achieved. His name was Amen; and it provides a fitting comment
upon his scheme.

[Illustration: Fig. 13. Illustration of Elberfeld-Barmen hanging
electric railway. From _The Electrical Industry_ (Books on Business),
published by Messrs Methuen.]

Several electric flying-machine ideas found their way on to the patent
records. In 1893 a Frenchman registered a design for an air-ship with
a cigar-shaped body and electrically-driven propellers. There was,
however, more originality in an American idea that the progress of
trains on the overhead railway might be assisted by the action of
balloons in taking the weight of the cars off the rails. Curiously
enough, other original inventors tried to get the opposite effect, by
devising magnetic arrangements to increase the adhesion of the wheels
to the rails.

More plausible forms of super-ingenuity have been exercised in
connection with established modes of electric traction.

For the conduit system one inventor suggested a kind of reversion to
the 'continuous valve' of the old atmospheric railway. The slot of the
conduit was closed by a continuous series of springs which would be
opened in succession by the plough as it passed along. This arrangement
was actually tried on an experimental track in London. Another inventor
proposed a novel plan for keeping the conductor in a conduit free from
damp. The conductor was to be made hollow, so that hot air could be
pumped through it to dry off any accumulated moisture.

[Illustration: Fig. 14. The Heilmann electric locomotive--a generating
station on wheels. The general arrangement of this locomotive should
be compared with that of the modern electric turbo-locomotive
described on p. 130 and illustrated in Fig. 15.]

The most entertaining freak in connection with the trolley system
was a device to enable two lines of car to use a single trolley wire.
Cars going in one direction were to carry a double-ended inclined plane
which would lift the trolley wheels of passing cars off the wire and
let them slip back again. The only drawback to this arrangement was
that it would not work.

Another inventor who was apparently impressed with the noise of trolley
wheels on the wires designed a trolley head fitted with a pneumatic
tyre. If he could have persuaded indiarubber to be anything but one of
the best of insulators, he would have been completely successful.

One of the best known of electrical freaks--the Heilmann locomotive
(Fig. 14)--is a very good example of the way in which an invention may
be tried with enthusiasm, rejected with contumely, and revived at a
much later date in an improved and more promising form. The Heilmann
locomotive was practically a generating station on wheels. It carried
a boiler and engines, which drove a dynamo, the current from which was
led through controllers to motors coupled to the wheel axles. It was
an enormous affair, over 18 metres long and running on sixteen wheels;
extensive trials were made with it on the Western Railway of France in
the early nineties. Some advantage was gained in smoothness of running,
ease and uniformity of control, and improved acceleration; but its
great weight, cost, and complexity were against it. In spite of the
cordial support given to it by railway engineers, it was soon relegated
to the scrap-heap.

[Illustration: Fig. 15. Electro-turbo-locomotive built by the North
British Locomotive Company for experimental purposes. This locomotive
is a 'generating station on wheels.' It carries a steam turbine
driving a dynamo which supplies current through a controller to motors
geared to the axles.]

The Heilmann locomotive, it will be noticed, is similar in principle to
the petrol-electric systems of propulsion now in use for road traction.
But it is probable that the idea would never have been heard of again
in connection with railway work had it not been for the appearance of
the steam turbine. It was natural that the locomotive engineer should
consider how the turbine could be applied to his purposes; and the
first step in this inquiry made it plain that some electric method of
control was necessary between the high-speed turbine and the driving
axle.

Consequently, when the engineers of the North British Locomotive
Company set to work in 1909 to design an 'electric turbo-locomotive,'
they produced something not at all unlike the Heilmann locomotive. The
equipment consists of a steam turbine, with elaborate condensing plant,
a generator, and a group of driving motors (Fig. 15). The turbine runs
at 3000 revolutions per minute and drives a continuous-current dynamo,
the current from which passes through controllers to four motors which
can be run in series, or two in series and two in parallel, or all in
parallel, according to the draw-bar pull required. Trials with this
locomotive were begun early in 1910, but it is yet too early to say
whether it will be more fortunate than the Heilmann locomotive, and
whether it is likely to delay the advance of the electric locomotive
proper, fed with power by overhead wires from a central power station.

[Illustration: Fig. 16. Diagrammatic sections of the Behr electric
mono-rail car. The car is balanced on the summit of a continuous
trestle and is designed for speeds up to 120 miles per hour.]

The possibilities of high speed on a mono-railway, and especially
an electric mono-railway, have acted like a will-o'-the-wisp to the
imaginations of many engineers. Of the various systems suggested, only
one--the gyroscopic mono-railway invented by Mr Brennan--seems likely
to survive; and even in that case victory under practical conditions is
not yet certain.

At Ballybunnion there is a steam mono-railway which has been at work
since 1888. It has had, so far as I am aware, no imitators; but its
engineer, Mr Behr, retained so much faith in the principle that he
decided to apply it to the problem of high-speed electric traction.
During the 1900 session he promoted a Bill for the construction of a
mono-railway between Liverpool and Manchester. There was tremendous
opposition from the existing railway companies, which brought experts
to prove that Mr Behr was a vain dreamer; but the Bill succeeded. The
promoters, however, found it much harder work to raise capital for the
project. They needed close upon £3,000,000, but the public response to
the first invitation was so small that the scheme was abandoned.

The line, as projected, was nearly 35 miles long; and a speed
of 100 miles per hour was intended, reducing the time of the
Liverpool-Manchester journey to twenty minutes. At each end of the line
(which was a double one) a steep gradient was arranged to facilitate
starting and stopping--an arrangement, by the way, which is adopted to
a certain extent on London tubes. The track itself was shaped like an
inverted V, and practically the whole of the weight of the cars was
borne upon a rail at the top. The wheels, therefore, were right in
the centre of the car, which balanced itself on the trestle with its
centre of gravity below the rail. Each side of the trestle carried two
guide-rails which bore against free-running horizontal wheels on the
car to prevent any undue lateral movement. Each car was designed to
carry four motors with a total normal capacity of 160 horse power and
an overload capacity up to 320 horse power. The rails for carrying the
current were placed on the track in very much the same position as the
ordinary rails occupy on a normal railway.

In another form of mono-railway--the Kearney high-speed railway--the
wheels are placed below the car and run on a single rail laid direct
on sleepers. The cars are held upright by flanged wheels on the top,
running on a rail fixed to the roof of tunnels or to standards not
unlike those of an overhead trolley. This railway has been exhibited in
the form of a model.

[Illustration: Fig. 17. The Brennan gyroscopic mono-railway.--The
car is electrically driven, and its equilibrium is maintained by the
action of two gyroscopes, also electrically driven.]

Mr Brennan's gyroscopic mono-railway was first shown, in a small size,
at a conversazione of the Royal Society in 1907. Full-sized cars were
constructed later, and one was seen at work during the Japan-British
Exhibition of 1910. The distinguishing feature of the vehicle is the
use of two gyroscopes (electrically driven), one horizontal and the
other vertical, to maintain the car upright on a single rail, even
when loaded unevenly and running at a fair speed round sharp curves.
From one point of view, the gyroscopic car is no more wonderful than
a spinning top, but the spectacle of a vehicle running steadily on a
single rail was so extraordinary that the interest of the whole world
was immediately aroused. Support was given to Mr Brennan's experiments
by the India Office and the Colonial Office, on the ground that a
railway which required only one rail, and was more or less independent
of both curves and gradients, would be of great value in districts
where the ordinary two-track railway might be both inconvenient and too
costly. One drawback to the arrangement is the necessity of fitting
each vehicle with gyroscopes, which are expensive and delicate pieces
of apparatus. But the ingenuity of the invention is so great that Mr
Brennan ought to reap the reward of seeing a gyroscopic railway in full
operation before long.

The only electric mono-railway actually at work is the 'hanging
railway' at Elberfeld in Germany (Fig. 13). This railway is an
evolution from the system of 'telpherage' which was devised in the
very infancy of electric traction for the transport of goods. The root
idea is to make the overhead wire carrying the current the track rail
as well, the whole contrivance--rails and cars--being suspended from
girders or cables supported by a series of standards or bridges. At
Elberfeld the cars pass over streets and also over canals. There are
no signs, however, that the 'hanging railway' will have any imitators.
In appearance and in cost of construction and operation it does not
seem to have any conspicuous advantages over a double-track overhead
railway. The system of telpherage is therefore likely to be confined
to the carriage of goods from one part of a factory to another, and
(in the form of cable-ways) to the handling of materials in mines and
other extensive engineering works. For such purposes it is having an
increasingly extended application.

[Illustration: Fig. 18. The 'Telpher' system of electrical locomotion
adapted to the transport of materials in a factory. The 'car' is
suspended from a girder and is operated by the driver in the same
way as an electric car. (From _Electrics_.)]

CHAPTER XVI

THE FUTURE

Nothing irritates an electrical engineer more readily than the
repetition of the phrase, 'Electricity is in its infancy.' The words
have been used by countless mayors and aldermen while 'inaugurating'
tramway or electric lighting schemes; they have been echoed by
innumerable journalists who persist in maintaining a Jules-Verne
attitude towards the electrical industry. And what disturbs the
electrical engineer is not only the banality of the phrase but the use
of it as a comment upon the achievements to which he has devoted his
life.

Nevertheless it will be admitted, from the rapid survey which we have
taken of electric traction, that the potentialities of electricity in
locomotion make an even stronger appeal than the actualities. Except in
one field--the tramway field--engineers have only touched the fringe of
possible developments in electric locomotion.

Even in tramway work we may, if legislative conditions improve and
if current becomes much cheaper, see a considerable development in
passenger and also in agricultural lines. Meanwhile the trolley omnibus
offers a prospect of extension in electric road traction; and there
is a great deal yet to be done with petrol-electric vehicles and with
electric automobiles in certain classes of transport.

The great field, however, lies in railway traction. There are 200
miles of electric railway in the United Kingdom; and there are nearly
13,000 miles of steam railway. Not even the most sanguine electrical
missionary will believe that this difference can be materially altered
within the next decade, but there is ample ground for faith in the
steady increase of the electrical figure. If the advance of electric
traction on railways must be slow, it is because financial and not
engineering considerations govern the speed of conversion. No railway
company can take a step involving hundreds of thousands of pounds, and
a revolution in working methods, without prolonged consideration and
elaborate preparation.

On roads, on tramways, and on railroads, the future lies with
electricity--wholly on railroads and tramways, perhaps not wholly on
roads. There is scope for it also at sea; and if our canals are worth
the cost of reconstruction on modern lines, electric haulage will
be used there on the model of the canal haulage installations which
exist here and there on the Continent. For marine work the advantages
of electricity have yet to be confirmed by practical experience; but
on land it has already proved that it supplies a means of locomotion
which is more efficient, cleaner and more attractive, and more closely
adapted to the needs and distribution of modern population than any
other.

The fashion for devising Utopias is not so popular as it used to be,
but in every ideal world which is more than a spiritual vision, and
in every intelligent forecast of an advanced civilisation, universal
electric transport is taken for granted. Electrical engineers are ready
to prove that this standard element in Utopia is available at the
present day on the basis which is the ultimate justification of all
engineering projects in this workaday world--the basis of profit.

Their confidence will be intensified when we approach the
'all-electric' age prophesied by Mr Ferranti in his Presidential
Address to the Institution of Electrical Engineers in 1910. Mr Ferranti
looks forward to a national scheme for the supply and distribution of
electric power. Under this scheme, the production of electricity would
be concentrated in one hundred huge power stations, using engines of
enormous capacity and acting as wholesale suppliers of electrical
energy to towns, railways, tramways, and factories. The price of
electricity would then be a fraction of what it is now; and all the
economies of electricity in action would be multiplied accordingly.
Technically, the scheme is quite feasible; and it could be realised
in the near future if capitalists and the Government could be brought
to appreciate the tremendous stimulus it would offer to industrial
activity and the effect it would have in conserving the power which is
latent in our coal measures.

INDEX

Acceleration, 23 _et seq._
on electric railways, 107, 110

Accumulators, 70
on air ships, 90
on ships, 90

Aeroplanes, 90

Alternating current, 30, 115

Automixte (petrol-electric), 85

Automobiles (electric), 70 _et seq._
advantages of, 80
hiring of, 75
in United States, 79

Batteries (electric), 13

Behr, F. B., 131

Blackpool, 37

Bournemouth, 38

Braking, 67

Brennan, L., 132, 134

Brighton line electrification, 117

Broadbent, F., vii, 116

Brunel, 8, 11, 17

Cab (electric), 78

City and South London Railway, 97

Conduit system, 28, 37, 126

Continuous current, 116

District Railway, 103, 119

Durtnall, W. P., 88

Dynamo, 13
reversibility of, 15, 67

Elberfeld-Barmen Railway, 125, 135

Electric traction
advantages of, 19 _et seq._
automobiles, 70 _et seq._
backwardness of, 46 _et seq._
on main line railways, 116, 122

Faraday, 13

Ferranti, 140

Fischer (petrol-electric), 85

Giant's Causeway, 93

Griffiths-Bedell (G-B.) system, 44

Gyroscopic railways, 132

Hanging railway, 125, 135

Heilmann locomotive, 128

Kearney, E. W. C., 133

Launches (electric), 73

Light Railways Act, 58

Liverpool Overhead Railway, 97, 111

Locomotive (electric), 12, 97, 108
Heilmann, 128
turbo-electric, 129

London
electric cabs in, 79
electric railways in, 97, 103
tramways in, 39, 53

Lorain system, 44

Lyttelton, A., 119

Marylebone, 81

Mavor, H., 88

Mersey railway, 97

Mono-railways, 131 _et seq._
gyroscopic, 132

Motor (electric), 14

Multiple-unit system, 99, 108

Omnibus (electric), 77
petrol-electric, 83

Overhead system, 17, 128

'Paragon' system (ship propulsion), 87

Petrol-electric system, 82 _et seq._

Provisional Orders (Tramways), 48

Railless traction (_see_ trolley omnibus)

Railways
atmospheric, 7
cheap power for, 113
experimental electric, 16
finance of, 100
opposition to, 6
pioneer electric, 92, 96
rope, 7

Raworth, J. S., 68

Regenerative control, 67

Series-parallel system, 32, 115

Ship propulsion, 88

Siemens, vii, 14, 16, 114

Signalling (automatic), 112

Single-phase system, 120

Starting torque, 23 (_see_ also acceleration)

Stephenson, vii, 5, 9

Storage batteries, 70 _et seq._

'Stud' system, 42

Telpher system, 136

Third rail, 16

Three-phase system, 118

Torquay, 44

Trackless trolley (_see_ trolley omnibus)

Trailers, 26

Tramcars
equipment of, 31

Tramroads
early, 4

Tramways
accumulators on, 20
conduit, 28, 37, 126
cost of, 53
generating equipment for, 22
inter-urban, 50
legislation for, 47
municipal, 49
overhead system on, 17, 128
statistics, 27, 28
surface-contact, 28, 42

Tramways Act (1870), 95

Trolley omnibus, 56, 60 _et seq._
in relation to tramways, 65

Trolley system 17, 29 _et seq._
bow, 31

Tube railways, 97

Turbo-electric locomotive, 129

Veto (tramway), 47, 51

Waterfalls
electric power from, 94

Watt, vii

Wheatstone, 14

Wolverhampton, 44

Workmen's fares, 53

Yerkes, C. T., 104

_Cambridge:_

PRINTED BY JOHN CLAY, M.A.

AT THE UNIVERSITY PRESS

Transcriber's Note:

Italics are indicated by _underscores_.

Bolds are indicated by =equal signs=.

Small capitals have been rendered in full capitals.

Footnote is placed to the end of chapter.

A number of minor spelling errors have been corrected without note.

*** End of this LibraryBlog Digital Book "Electricity in Locomotion - An Account of its Mechanism, its Achievements, and its Prospects" ***

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