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.
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,[Pg 59] 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 1-1/2d. or 2d. 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.
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.'
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.
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,[Pg 59] 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 1-1/2d. or 2d. 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.
Fig. 7. The 'auto-trolley' system of electric traction applied to the haulage of goods in a German quarry. (From Electrical Industries.)
ADAM GOWANS WHYTE, B.Sc.
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