Abstract: A brake control valve arrangement for controlling application of a braking force includes an electro-pneumatic brake control valve block including a hold valve and a vent valve (PRESSURE CONTROLLER), a main regulator valve (RELAY VALVE) and an emergency and a variable load control pressure regulator. The valve block has an inlet for a brake supply pressure, and an outlet in pneumatic connection with a brake cylinder. A pilot pressure into the main regulator valve from the variable load control pressure regulator is controlled by a remote release solenoid valve (CONTROL CHAMBER VENT MAGNET VALVE). The remote release solenoid valve adapted to vent brake cylinder pressure to atmosphere when de-energized thereby enabling release of the wheel braking force via the main regulator valve.

Abstract: An electropneumatic rail brake system configured to provide emergency braking including an emergency magnet valve which controls air flow into an emergency regulator valve, which valve has an emergency back-up chamber. The emergency regulator provides an output pressure nominally equal to the variable load pressure and no lower than the tare back-up. The magnet valve is closed when energized and when de-energized, pressure is allowed into the emergency back-up chamber, Regulation of the brake cylinder pressure continues during an emergency application such that the brake cylinder pressure applied during an emergency stop does not drop below a predetermined level. In the event of power-loss during an emergency brake stop, the nominal emergency brake pressure is applied to the brake cylinders.