A TRACTOR THAT PUSHES
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and PULLS SOME special features have been incorporated in the new Chenard-Walcker tractor which Hall, Lewis and Co., Ltd. has just supplied •to the London, Midland and Scottish Railway Co. It is one of an order of three; the other two have been sent to depots in the north of England, and the third one, which has but recently been completed, is destined for work in London.
Tractor work in a railway yard is of an exacting nature, and in the case of this new appliance the railway company has ordered the fitting of a stoutly constructed front bumper, so that the tractor may be utilized for pushing trailers and other vehicles in the goods yards.
The thrust-load on the bumper is borne by two pairs of L-sectioned steel girders which are bolted to the chassis side-members, the buffer plate being a heavy baulk of timber reinforced for its full length with steel angle-plates.
Another feature of equipment • Ordered by the railway company as an experiment is the servo-operated Westinghouse braking apparatus having a flexible hose-coupling for connection with a similar fitting on the trailer, so that depression of the brake pedal actuates expanding shoes in drums on the rear axle of the tractor and-on both axles of the trailer. The necessary exhaust action for the Westinghouse equip meat is obtained from the engine induction system.
The railway company has specified the usual disc wheels, to Which pneumatic tyres of 33-in. by 5-in. section have been fitted, the rear wheels of the •tractor having twin tyres.
Chenard Waleker tractors are nowadays built under licence in Britain at the works ofHall, Lewis and Co., Ltd„ at Maindy, near Cardiff, the engines, gearboxes and back axles being importedfrom the parent concern in France. The latest model is interesting in many respects. It has a five-speed gear box, a lockable differential, and a power take-off for winch and other work. The .engine is an overheadvalve unit developing 44 b.h.p. which
makes fast road speeds quite easy of attainment with heavy loads. The weight of the tractor being cwt., it comes within the class for which, the_ speed limit is 20 m.p.h. The fifth speed provided in the gearbox is an interesting feature, being an indirect drive and only intended for specially fast stretches. The makers claim that 40 m.p,h. can easily be exceeded with the use of this supplementary gear. The power take-off spindle protrudes from the back of the gearbox and is splined for the purpose of coupling; it is commonly used to operate a winch for hauling loads aboard a trailer, dragging tree trunks, etc., anti in this way a 3-ton pull can be obtained at an engine speed of 1,000 r.p.m.
The differential lock is operated by a cable from a lever placed near the driver's seat, and is a most useful adjunct when lands have to be dealt with over soft ground. The duties of a tractor so often take the machine away from made roads and call for heavy haulage in yards and fields.
A patent coupling device for trailer drawbars is used on Chenard ,7.Valcker tractors, and with it is embodied a hand operated turnscrew arrangement by which the front wheels of the trailer can be lifted clear of the ground. One of the important advantages of this feature is that it greatly facilitates the backing of trailers into awkward and confined spaces. It is possible to lock the front-axle turntable of the trailer when in the raised position for the purpose of towing at .speeds.
The power unit of the Chenard Walcker tractor is familiar to commercial-motor users, and is of the orthodox overhead-valve type, the valves being operated by push rods. The bore is 79.5 ram. and the stroke 150 mm; Reference must be made, however, to the ingenious system of cooling and filtering the oil. The oil is pumped through a duct in the crankshaft leading to the flywheel, which is hollow. Centrifugal force causes dirt in the oil to be flung outwards to the periphery, of the wheel, the clean oil finding its way back to the crankcase by anothet duct in the main shaft. Vanes on the forward face Of the flywheel assist in cooling the oil while it is being cleansed.
We are informed, that over 5,000 Chenard-WaIcker tractors are in service with French railway companies, the P.L.M. Railway having replaced its horse's by them.