Emergency valve cover containing a quick service valve

A fluid brake control system having a brake pipe, a control valve of the ABD type including a quick action chamber in a pipe bracket and an emergency portion housing secured to the pipe bracket, the housing containing an emergency slide valve means selectively operable axially for governing venting of the quick action chamber, the slide valve means being operable axially from a normal position to fully actuated and intermediate positions in accordance with the sensing respectively of emergency and service rates of pressure reduction in the brake pipe and the slide valve means having a fluid differential operated abutment disposed between a first pressure chamber within the emergency portion housing on one side of the abutment subject to pressure of the quick action chamber and a second pressure chamber contained in an emergency portion cover on the other side of the abutment connected by a passage to the brake pipe wherein an improved emergency portion cover on the other side of the abutment has secured thereto quick action control means for at least periodically venting fluid from the brake pipe as long as the brake pipe is vented at a service rate comprising;

• a. normally closed quick action poppet type valve means operably connected to the abutment and opened when the emergency slide valve means is in the intermediate position in response to the service rate of reduction in the brake pipe, and
• b. venting means permitting passage of fluid from the brake pipe through the quick action valve means in series with an exhaust choke for venting fluid from the brake pipe at a controlled rate in response to actuation of the emergency slide valve means to its intermediate position upon sensing a service rate of reduction in the brake pipe.