Abstract: A brake control valve includes a housing, a quick braking chamber and a piston subject to brake pipe pressure on one side of the piston. A bore in the housing connects the quick braking chamber at a first end and the one side of the piston at a second end. A first valve is in the housing at the first end of the bore. A first operator is in the bore for opening the first valve for a range of positions of the piston. The bore has a first portion of a first diameter and a second portion of a second diameter larger than the first diameter. The first bore portion connects the one side of the piston to the second bore portion. A first operator in the bore is connected to the piston. A seal on the first operator is dimensioned to form a seal with the first bore portion and not with the second bore portion.

Abstract: A brake control valve includes a housing, a quick braking chamber and a piston subject to brake pipe pressure on one side of the piston. A bore in the housing connects the quick braking chamber via a first port at a first end and the one side of the piston at a second end. The bore has a first portion of a first diameter and a second portion of a second diameter larger than the first diameter. The first bore portion connects the one side of the piston to the second bore portion. A first operator in the bore is connected to the piston. A seal on the first operator is dimensioned to form a seal with the first bore portion and not with the second bore portion. The seal is located on the operator to lie in the first bore portion for a first segment of the range of piston positions and to lie in the second bore portion for a second segment of the range of piston positions.

Abstract: Device and method for determining a wheel braking pressure and/or an admission pressure in a braking system in which pressure medium is introduced from a reservoir for the pressure medium having an admission pressure into a wheel brake through at least one shutoff device for inlet and/or outlet and/or passage of a pressure medium, it being possible to remove pressure medium from the wheel brake through at least one means delivering the pressure medium. In so doing, a pressure quantity representing the admission pressure is estimated, at least one operating state of at least one actuator in the braking system is detected and the wheel braking pressure is estimated as a function of the estimated admission pressure and the detected operating states.

Abstract: During ASR control of spinning drive wheels, the pressure level in the wheel brake with the highest pressure level is modulated by driving a switching valve USV which affects the pressure in all the wheel brakes of the brake circuit, whereas the pressure level in the other wheel brake or brakes is controlled by way of wheel-specific inlet and outlet valves. The intake control valve ASV is kept open through the entire ASR control period. As a result, the electrically actuated ASV can be replaced by a hydraulically actuated ASV.

Abstract: A control valve having, in a series with a first inlet valve of a quick brake volume, two different rates of flow restrictions operable as a function of the position of the piston. The first flow rate of one first restriction is insufficient to cause the piston to a braking position for applying a minimum service application for first range of piston positions which would generally be produced by the mechanical vibration. The second restriction has a greater flow and will accelerate the piston to a braking position for a second range of piston positions which will be produced by the reduction of the brake pipe pressure on one face of the piston. By providing two flow rates, the valve becomes insensitive to mechanically produced forces while maintaining the reaction time of the valve to fluidically produced reduction of brake pipe pressure.

Abstract: The electropneumatic control system for the pressure in the main air pipe (37) of compressed air brakes of rail cars is provided with one inlet and one outlet solenoid valve (3 and 4) to control the pressure in a control chamber (26) of a relay valve (19). The inlet solenoid valve (3) and the relay valve (19) are supplied with compressed air from a main reservoir pipe (34). The relay valve controlled by the pressure in the control chamber (26) against the pressure in the main air pipe (37) controls the compressed air lead-in and lead-out for the main air pipe (37). To avoid the undesired response of the relay valve (19) to pressure changes elsewhere in the main air pipe (37), the two sides of the piston (20) of the relay valve (19) are closed without any throttling by way of the secondary valve parts (13 or 14) of the two solenoid valves (3 and 4) in the unactuated state of the control system (2).

Abstract: A quick service limiting valve device for a freight brake control valve employing a primary valve in a fluid flow path via which brake pipe air is connected to the brake cylinder during a secondary phase of quick service to propagate the brake pipe reduction signal until the brake cylinder pressure acting on the limiting valve control piston effects closure of the primary valve to terminate the quick service flow of brake pipe air to the brake cylinder when a predetermined brake cylinder limit pressure is realized. A secondary valve is arranged to interrupt the brake pipe to brake cylinder flow path downstream of the primary valve in the event leakage at the primary valve causes the pressure acting on the quick service limiting valve control piston to exceed the predetermined limit pressure.

Abstract: A low brake pipe pressure detecting circuit for a railway train is provided in conjunction with a conventional vent valve device typically associated with the locomotive brake valve device to exhaust the train brake pipe pressure and thereby effect an emergency brake application. Conventional pneumatic pilot valve devices are interconnected with the vent valve device to actuate the vent valve device only for a limited duration following which the pilot valves are automatically reset to effect closure of the vent valve device preparatory to recharging brake pipe pressure to obtain a subsequent brake release.

Abstract: A housing has a triple valve coaxially adjoining a proportioning piston valve end-to-end, the triple valve having supply, lap and exhaust positions for governing pressure in a brake cylinder; and the proportioning piston valve being operable to sense an emergency signal in a brake pipe for delivering fluid from an emergency reservoir to the brake cylinder after the brake cylinder has been charged to substantially service pressure from an auxiliary reservoir. The triple valve and the proportioning valve piston are biased in opposite directions by the same biasing spring.

Abstract: An upgraded railway freight car brake control valve device comprises a novel emergency valve portion that embodies therein a plurality of simple and inexpensive poppet valves that replace yet perform the same functions heretofore performed by more expensive slide type valves which slide valves, and the flat seats upon which they slide as they are shifted from one position to another, in their manufacture require a considerable amount of accurate machining thus increasing the cost of the valve device of which they are an important part.