TRIPLE VALVES 211 



at equalization to an amount that gives the proper braking 

 power with the proper brake-pipe pressure while reducing 

 the danger of wheel sliding to a minimum. As a protection 

 against excessive brake-cylinder pressure during service appli- 

 cations, due to too high brake-pipe pressure, there is provided 

 a reducing valve that operates only in service applications 

 and is automatically cut out of service when an emergency 

 application is made. This constitutes the service-application 

 safety-valve feature of the L triple valve. 



PIPING DIAGRAM OF LN EQUIPMENT 



Fig. 1 shows the piping diagram of the type LN passenger 

 equipment. The general arrangement of the piping and the 

 location of the parts of this equipment are practically the 

 same as in the ordinary PM passenger equipment, except that 

 with the LN equipment the L triple valve replaces the older 

 form of triple valve and the N brake-cylinder head, which is 

 especially designed for use with the type L triple valve, takes 

 the place of the older form of brake-cylinder head. Besides, a 

 supplementary reservoir is added to the older form of passenger- 

 car equipment. 



The brake-pipe, which extends throughout the length of 

 the car, has a branch pipe that connects to the brake-pipe 

 connection on the brake-cylinder head. The centrifugal dirt 

 collector in the branch pipe takes the place of the brake- 

 pipe strainer formerly used with the car equipment. The 

 cut-out cock in the branch pipe is for the purpose of cutting 

 out the brake on that car when necessary. The function of 

 the auxiliary reservoir is the same as in the older equipment. 

 The pipe leading from the ^auxiliary reservoir is connected to 

 the brake-cylinder head at the auxiliary-reservoir connection 

 and this reservoir is charged through the triple valve the 

 same as in the older form of equipment. The supplementary 

 reservoir, which has a capacity about two and a half times 

 that of the auxiliary reservoir, carries an extra supply of air, 

 which assists in obtaining the graduated release of the brakes 

 and makes possible the very high brake-cylinder pressure 

 obtained in emergency applications. Also, it recharges the 

 auxiliary reservoir quickly, after a service application and 



