248 NO. 6 ET LOCOMOTIVE BRAKE 



The double-heading cock (in the brake pipe just under the 

 brake valve) is for the purpose of cutting out the automatic 

 brake valve from the brake pipe on the following locomotive 

 of a double-header. It is closed when its handle is parallel 

 with, and open when its handle is at right angles to, the pipe. 



The by-pass for charging dead engine consists of a pipe 

 leading from the brake pipe O to the main-reservoir pipe, 

 together with a cut-out cock, a strainer, and a non-return 

 check- valve. The purpose of this arrangement is to provide 

 a means of supplying air for the distributing valve and brake 

 cylinders of a dead engine (or one with a disabled air pump) 

 from the supply in the brake pipe that is furnished by the 

 other engine. When necessary to use the by-pass arrange- 

 ment, the double-heading cock in the brake pipe must be 

 closed and the cut-out cock in the by-pass pipe opened. 

 When the by-pass arrangement is not in use, the cut-out cock 

 in the by-pass pipe must be closed. 



The brake-cylinder pipe leads from the distributing valve 

 to the driver and tender brake cylinders; also it connects 

 with the engine-truck brake cylinder when the engine is 

 provided with a truck brake. 



The driver, tender, and truck-brake cut-out cocks are for the 

 purpose of cutting out their respective brakes in case the 

 brake becomes disabled. 



The choke fittings in the tender and truck brake-cylinder 

 pipe have a restricted opening that will allow air to pass to 

 and from the engine-truck and tender-brake cylinders fast 

 enough to operate their brakes properly; but if the hose con- 

 nections to these cylinders should burst or become uncoupled, 

 the choke fitting will restrict the flow of air so that the dis- 

 tributing valve can hold the pressure up to the standard in 

 the other brake cylinders; hence, the bursting of a tender- or 

 truck-brake hose will not disable all the locomotive brakes 

 during the stop. 



The B-6 feed-valve reduces the main-reservoir pressure to 

 the standard desired for use in the train brake pipe. 



The C-6 reducing valve reduces the main-reservoir pressure 

 to 45 Ib. for use in the independent brake valve and in the 

 air-signal system. 



