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.'