A New Development in Pneumatic-tyred Railcars
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development of the Micheline pneumatic-tyred railI_ car which aroused so much interest on its visit to Bngland, is proceeding steadily in France and the Freneh colonial empire. A dozen regular services are already being operated in various parts of the country by Micheline railcars, and several new ones are to be inaugurated in the near future.
In the French colonies the Tunis Railway Co. is running a Micheline railcar experimentally, whilst in Madagascar a successful regular service has been instituted between the port of Tamatave and Antananarivo, making a rapid liaison between steamers and the capital.
In the case of this particular service an important saving of time is effected, as the ordinary train takes 15 hours to complete the journey, whilst the railcar performs it in eight hours. The track here rises to an altitude of 4,000 ft., and includes a large number of sharp curves, which can be negotiated at a higher speed than is possible with the steam train.
Another new service employing Micheline railcars is to be started next week by the Nord Railway Co. on the route from Douai to Valenciennes.
A new type of Micheline 36-seater has just been delivered to the French State Railway concern, and is shortly to be put into service, probably in the Cherbourg district.
This new vehicle marks a definite stage in the evolution of pneumatic-tyred railcars. Earlier models had much of the road motor about them, just as the earliest automobiles retained so many characteristics of the horse-drawn vehicle, The new Micheline has obviously been designed by railway engineers for the particular job in hand. It is mounted on two six-wheeled bogies and has the characteristic railwaywagon suspension by coil springs at the ends of the traverses. This suspension is supplemented, however, by long half-elliptic springs disposed externally beneath each wheel hub and linked ta the coil-spring supports.
The engine is an Hispano-Suiza 110-mm. by 140-mm. sixcylindered unit, developing 140 blip, at 2,200 r.p.m., and the drive is conveyed to all six wheels of the driving bogie, chain transmission being employed.
A Lamblin aviation-type cylindrical radiator is mounted on each side of the control cabin, which is located forward and is built into the roof of the car.
Spring-loaded skids Make permanent contact with the rails
and maintain current for the electric signalling indicators, etc., which would otherwise be insulated by the rubber tyres.
• During test runs under full load the car has shown a petrol-consumption return of 9 m.p.g. The maximum speed is 95 k.p.h. (69.023 m.p.h.), and an average of 53i m.p.h. can. be maintained regularly.
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Curves can safely be negotiated at the following speeds :— Radius : 500 tn., 80 k.p.h.; 350 m., 70 k.p.h. ; 250 m., 60 k.p.h. ; 200 m., 50 k.p.h. • 100 m., 40 k.p.h. In the matter of acceleration, a speed of 80 k.p.h. can be attained from rest in a distance of 1,200 m.
In braking, the normal stopping distance at 80 k.p.h. is 200 m., but with full emergency braking this figure is reduced to 120 m. on dry rails and 150 m on wet rails.
In addition to 36 passengers, 540 kilos. of luggage can be carried, the total weight of the vehicle with its load being then about 9.6 tons. The unladen weight of the vehicle is 6i tons, its overall length 13.6 m., and overall width 2.65 m. The tyres employed ara special railway-type 125 mm. by 610 mm. Michelins, with an external diameter of 875 inui. These tyres are maintained at .a pressure of 7 kg. per sq. cm., or 99.4 lb. per sq. in. This high pressure indicates the special nature of the tyres which the Michelin Co. is making for "railway work.
Lockheed hydraulic braking is employed and the bodywork of the ear is constructed almost entirely of aluminium.
Micheline railcar services are proving useful in linking up towns with important railway junctions where fast main-line trains make regular halts. A case in point is the CreilBeauvais service, inaugurated a few weeks ago ; this service Las brought Beauvais within n hours of Paris and is already much utilized by business men.
• Many fast trains to and from Paris stop at Creil and connect up with the railcar for Beauvais, which is 37 kiloms. from Creil junction. One of the longest regular services in operation is run by the State Railway between Argentan and Granville, a distance of 131 kiloms. Here the railcars connect up with the Paris express, and a saving of two hours is effected over the old steam-train connection.