Abstract: An assembly may be provided that may include a valve body having a piston within a piston bore in the valve body, the piston bore including a valve chamber section and a brake pipe section such that a pressure differential between the valve chamber section and the brake pipe section moves the piston within the piston bore. The assembly may also include a slide valve seat coupled to the valve body. The slide valve seat may include a brake pipe port, an additional discharge channel pilot valve port, and at least one exhaust port, and a slide valve coupled to the piston and configured to move along the slide valve seat with the piston. The slide valve may be configured to move between at least a piloting position and an exhaust position to vary an exhaust rate of the brake pipe section and an exhaust rate of the valve chamber section during braking.

Abstract: An uncoupling valve for use in rail car brake systems having a pressurized supervisory pipe includes opposed piston motors which hold the valve open long enough to depressurize the supervisory pipe and cause an emergency brake application, when two cars are uncoupled accidentally. On the other hand, the valve includes a controlled source of pressure for overpressurizing one of the piston motors to hold the valve closed to prevent depressurization of the supervisory pipe, when two cars uncoupled intentionally.

Abstract: An inexpensive emergency valve device embodies a first movable abutment, subject on its respective opposite sides to the pressures in a brake pipe and a quick action chamber, that, upon a service rate of reduction of brake pipe pressure, unseats a poppet valve from one of two valve seats between which it is disposed so that, while unseated from both valve seats, fluid can flow at a service rate from the quick action chamber, one side of the first abutment and both sides of a second abutment, operatively connected to a combined emergency and brake pipe vent valve to atmosphere so long as brake pipe pressure is reduced at a service rate thereby preventing an emergency brake application.

Abstract: A railway freight car brake control valve device comprises a novel emergency valve portion that embodies therein a plurality of simple and inexpensive diaphragm-type valves certain of which are subject on their respective opposite sides to brake pipe pressure and quick action chamber pressure. The construction and arrangement of these diaphragm-type valves are such that a service rate of reduction of brake pipe pressure enables flow of fluid under pressure from the quick action chamber to the brake pipe at a service rate, and an emergency rate of reduction of brake pipe pressure enables one of these diaphragm-type valves to effect the supply of fluid under pressure from the quick action chamber to a brake pipe vent valve device the resulting operation of which vents fluid under pressure from the brake pipe to atmosphere at an emergency rate to thereby cause an emergency brake application.