Abstract: Three embodiments of a hydraulic braking system are shown and described. Each embodiment provides a precisely controlled hydraulic braking system for a railway vehicle, which features a pilot pressure controlled brake control valve. The pilot pressure is selectively varied by operation of pressure control and flow control valves so that the power requirements for the hydraulic braking system are minimized. The braking system can be used with either spring-apply, pressure-release or pressure-apply, spring-release braking actuators. An auxiliary hydraulic system is provided to operate the brakes if the primary hydraulic system should fail. The pilot pressure fluid which operates the brake control valve can be either hydraulic or pneumatic. The brake control valve can be provided with a pneumatic emergency brake override control.

Abstract: A hand pump in which the piston is double acting, incorporating a check valve to limit the manual force to operate the pump and having a pressure release valve actuated by the pump handle in home position.

Abstract: Brake apparatus, particularly one in which the brake may be both actuated and released by a hydraulic force, held engaged by a mechanical force and in which a strong spring force, tending to restore the brake, prevails while the brake is held engaged; brake applying pressure, after the brake is engaged, is at first slowly released, hydraulic pressure employed to release the brake is maintained at a minimum value even though the brake may be released and certain conditions are sensed for coincidence before generating a signal indicating that the brake release conditions are complied with.