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YORKSHIRE TROLLEYBUS DEVELOPMENTS.

6th September 1921
Page 23
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Page 23, 6th September 1921 — YORKSHIRE TROLLEYBUS DEVELOPMENTS.
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Which of the following most accurately describes the problem?

The Adoption of the Front Wheel Drive to Railless Vehicles.

30ST-WAR difficulties of tramway

managements in the direction of roviding renewals of track have led to -a avelopment of railless trolley-bus under',kings, and a close scrutiny of the more axible system is being made by anthoriies which find themselves unable to meet le huge capital outlay necessary for the ,ying Of new tram tracks, or renewing lose which have become worn out thug the war. Bradford has introneed a double-deck vehicle, of a type mina to a rail tramway car, and is gilding a six-wheel car of novel design. Leeds was among the pioneers in the ligation of the railless Vehicle, and, in at city, double-deck vehicles are ready m the road.

Experiments with the Object of improvLg the mechanical arrangements of the iilless vehicles are being carried out by any authorities, and the managements meerned, it would appear, find the 7eatest difficulty, with the new type of

to be in guarding against the illfeetvof vibration as set up by the heels-being in direct contact with road irfaces of various degrees of roughness. ity and suburban roads, upon which ie railless ears mostly travel, are those filch have stood the shock of heavy artime traffic most, and; consequently, :e•generally in very bad condition.

In looking at the matter from another tint of view it will also he seen that the )0TISOrd of the trolley-bus—mostly men ith tramway experience—haVe here sine into contact with a problem which by no keens so severe in the case of ?hides travelling upon rails. In build.g a trolley-bus, entirely new notions ive to be conceived both in regard to 3wer requirements and springing when compared with a tramcar. The ratio between the power required for starting a trolley-bus and the ordinary running power is much greater than in the case of a rail vehicle, and the springs, also, must have much greater shocks to withstand. Generally, it is in this direction that the earlier vehicles of the railless type failed most.

Developments to relieve these difficulties haveproceeded uponseveral lines.

Petrol lorry practice has been followed in developing the chassis parts and the springs in Natty .instances, hot in one or two cases notable departures from previously recognized custom have been made. This has been the case where the front-wheel drive has been adopted as in the case of Leeds and Keighley. The idea behind the adoption of the frontwheel drive has been that the rear wheels cirry three-quarters of the,vload of a vehicle of this type, and the front wheels do not, therefore, receive such immense shocks, and the motors ate not subject to such rough treatment.

In the case of both Leeds and Keighley, the design of Mr. G. A. Bishop, of Leeds, has been adopted and the parts built under licence from the Electric Traction Co., of Leeds, with which Mr. Bishop is connected. _The power units differ in the case of the two towns, but this is because in the case of Keighley it was desired to adapt existing vehicles and use asmany aspossible a the existing parts. Motors of usual pattern are mounted upon the front axle and drive through a reduction gear to the front wheels on the vehicles in use in Leeds, but with the only Keighley vehicle which has, as yet, been adapted for front-wheel drive the driving wheels of the Cedes-Stoll pattern, which have the motors in the hub, have been brought from the rear to the front. The suspension and steering system of ths Leeds and Keighley cars are the same, however.

For all practical purposes, the front portion can be_ considered as a twowheeled tractor in these vehicles, the steering and driving portions being incorporated in -one unit. The front aide forms the principal member of the substantial framework carrying life springs, and, in the case of the Leeds vehicles, supports the motor, and all this portion is steered through a rack and worm gear from the driver's at above.

The Leeds car has been working for a ,period of 18 months, and in actual experience on the road the claim that the motors have a longer .life under more favourable conditions in which they have to work has been substantiated, the department having in hand plans fur the fitting of a large number of cars of similar design, these including double deck vehicles to accommodate 60 passengers, In the case of Keighley, the alteration was carried out because it was found impossible to carry on on one route with the motors in the back wheels. The tests to which they were put in everyday use were too severe for continued running, there being an average gradient of 1 in 12 over the greater portion of 'a 3i mile run. The motors have since been re-designed by the Keighley Tramways manager. (Mr. J. A. Bromley) with a view to ease of adjustment and repairs, and, in the new. position, it is hoped that the service will continue.

Since the Keighley vehicle has been fitted with the front-wheel drive, an improvement of the running has been noticed, not the least interesting feature being the, feeling that the bus was being pulled, rather than driven from the back wheels, and the motiOn is more comfortable for the passenger. The steering of these vehicles is positive, the pull being in line with the direction in which the vehicle is travelling; and under test, when one wheel was made to pass over a railway sleeper repeatedly, the direction of travel was not altered in the slightest. This feature is of particular importance in driving upon a. rough road, no shocks being transmitted to the steering wheel. By the withdrawal of four bolts, the whole of the front unit can be removed, and in case of a failure in any part of the mechanism a new portion substituted in a couple of hours. The two rear wheels being nothing more than trailer wheels there is no possibility .of skid. Brakes are fitted to all four wheels.

High speeds are not expected from these vehicles, but with the Keighley bus two motors of 25 h.p, each are fitted— one in each wheel—and a steady eight miles per hour can be maintained up 11 steep hills 'which are encountered on ti route of the bus. On a trial run, it w interesting to wAch the ammeter. 11 starting on an incline the reading reach! as high as 90 amps. and then gradual settled down, according to the gradie and the speed, to between 70 and 4 Travelling steadily, however, there w always a reserve of power. The diffe ence between the power needed wht the roads were greasy as compared wi when they were dry, we were informe was tonally about seven horse-power.

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Locations: Bradford, Keighley, Leeds

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