Abstract: A method of and a system for determining a maximum brake pipe service reduction in the brake system of a train having a pneumatic brake on each car connected to a brake pipe which is controlled by a brake pipe controller. The method includes determining the status of the brake system throughout the train and determining a maximum brake pipe reduction for the brake pipe controller, using the status of the brake system, above which further reduction will not result in further brake application in the train. The determined maximum brake pipe reduction is displayed by itself or in combination with the brake pipe reduction produced by the brake pipe controller and/or used for automatic control.

Abstract: A vehicular wheel chock assembly and method of operation for use in providing automatic, positive chocking of one or more wheel of a vehicle upon setting of the vehicle's emergency/parking brakes and automatic retraction of the chock assembly upon release of the emergency/parking brakes. Retraction and extension air pressures are derived from the accessory air reservoir upon engagement and release, respectively of the vehicle's air powered parking or emergency brakes. Thus, the vehicle driver merely has to engage the emergency/parking brakes when parking the vehicle to cause the wheel chocks to be moved from their retracted positions to their engaged positions in front of and behind a vehicle wheel. In this way, the wheel chock assembly positively forces the wheel chocks into engagement with the parked vehicle wheels and the surface they rest on or positively collapses the chock assembly into a compact configuration at the underside of the vehicle on which the chock assembly is mounted.

Abstract: This invention relates to braking systems for railway vehicles in which a fall in brake pipe pressure is employed to initiate braking via a brake cylinder inlet valve.In accordance with the present invention, the brake cylinder inlet valve is rendered in-operative by the absence of auxiliary reservoir pressure, thus dispensing with the need for a complicated mechanical sequence requiring fine machining tolerances etc. and avoiding the necessity of employing an additional valve.The brake cylinder (BC) inlet valve 60 is operable by a diaphragm 54. When the system is fully charged, the brake cylinder inlet valve 60 is closed as shown in the accompanying drawing. The diaphragm 54 is subject to brake pipe pressure in chamber C and to auxiliary reservoir pressure in chamber D. In the absence of auxiliary reservoir pressure in chamber D, the pressure in chamber C holds the diaphragm in the position shown and prevents the ball valve 60 from being opened, thus preventing brake application until braking is demanded.