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

Abstract From the Canadian patent

Case No. 8389), ABSTRACT OF THE DISCLOSURE A freight brake control valve device in which the emergency piston slide valve is arranged to incorporate in, conjunction with the conventional service stability function provided thereby, an accelerated service application function in which a continuous local venting of brake pipe pressure is provided to hasten propagation of service rates of brake pipe reduction. A preliminary flow restrictor in one flow path and a primary flow restrictor in a parallel flow path control the quick-action chamber "breathing" rate such that the emergency piston is stabilized against movement to emergency position as long, as the brake pipe pressure reduction does …