RAILCAR BRAKE VALVE

An inexpensive emergency valve device embodies a cycling-type continual quick service valve operative by an abutment, subject on its respective opposite sides to the pressure in a train brake pipe and in a quick action chamber, in response to a service rate of reduction of the pressure of the fluid in a train brake pipe to repeatedly vent and supply fluid under pressure from and to a quick service volume disposed on one side of a diaphragm-type valve that is operatively responsive to the venting of fluid under pressure from this volume to effect the release of fluid under pressure from the quick action chamber to atmosphere at a rate faster than a service rate to cause joint cyclic operation of the continual quick service valve and the diaphragm valve to successively supply fluid under pressure from the brake pipe to and thereafter release fluid under pressure from the quick service volume at a certain rate and from the quick action chamber at a faster rate so long as fluid under pressure is released from the train brake pipe at a service rate. An emergency piston disposed within the quick service volume cooperates with the diaphragm valve in response to an emergency rate of reduction of the pressure in the brake pipe to effect operation of a brake pipe vent valve and a poppet-type valve that effects the supply of fluid under pressure from an emergency reservoir to a brake cylinder jointly with the supply from an auxiliary reservoir to cause an emergency brake application.