File:Air brakes, an up-to-date treatise on the Westinghouse air brake as designed for passenger and freight service and for electric cars (1918) (14763592112).jpg

Identifier: airbrakesuptodat00ludy (find matches)
Title: Air brakes, an up-to-date treatise on the Westinghouse air brake as designed for passenger and freight service and for electric cars
Year: 1918 (1910s)
Authors: Ludy, Llewellyn V., 1875- (from old catalog) American Technical Society
Subjects: Westinghouse air-brake
Publisher: Chicago, American technical society
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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when the brake-valve handle is in running posi-tion, 70 pounds pressure is carried in the brake pipe, and the com-pressor will slow^ down when main-reservoir pressure reaches 90pounds. If, however, the brake-valve handle is in lap, service, oremergency-application position, main-reservoir pressure is cut ofTfrom the excess-pressure head, and the compressor will continue tooperate until the main-reservoir pressure reaches the limit set by themaximum pressure head, to insure available pressure promptly torelease and re-charge the brakes on long and heavy trains. If the reversing-cock handle be turned to the position shown,the 110-pound feed valve will become operative, giving 110 poundsbrake-pipe pressure, which results in a corresponding increase inmain-reservoir pressure depending upon the adjustment of themaximum pressure head of the governor. Principles Involved. The principles involved in the high-speedbrake are (a) the friction between the brake shoe and the wheel, 106 AIR BRAKES
Text Appearing After Image:
3 Wa> W 02 w 3O ^ (si AIR BRAKES 107 that tends to stop the rotation, becomes less as the rapidity of rota-tion of the wheel increases, and (b) the adhesion between the wheeland rail remains practically constant regardless of the speed. Itwill thus be seen that, at high speeds, a greater brake-cylinderpressure, with corresponding increase of the brake-shoe pressure,can be used without danger of sliding wheels; but, in such a case,it is necessary to provide means for reducing this high-cylinderpressure as the speed of the train is decreased. This is accomplishedby the automatic reducing valve, which has previously beenexplained. Cars not fitted with reducing valves should not be attached totrains using the high-speed brake unless the brake cylinders are 6C ^ rc % ^ 5; 1.- t3 ^- 45 ^ 1 — ■■ — - — ■- Gi HCI 3, Id on B. ■ahhi e t/h Fig. 89. ^oo 400 600 eoo icco i^co it-cc leoo leoo ^oco c^co ^^oo peco ^eco jcooLength cf 5lopin Feet Diagram Showing Minimum Length of Stop f

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