Freight brake control valve having an emergency piston slide valve and graduating valve arranged to provide an accelerated brake application function

Abstract From the Canadian patent

Case No. 8396), ABSTRACT OF THE DISCLOSURE A freight brake control valve device in which the emergency piston is arranged to operate a pair of slide valves having lost motion therebetween to provide a continuous, local reduction in the brake pipe pressure in response to initial actuation of the emergency piston when a service rate of brake pipe pressure reduction is made in, order to quickly propagate a brake pipe pressure reduction wave along the train and accordingly provide an accelerated application of the train brakes. This accelerated application function in response to a service rate of brake pipe prssure reduction is achieved during movement of the emergency piston toward emergency …