Abstract: A railroad air brake system for truck mounted air brakes includes an ABDW valve and auxiliary and emergency reservoirs with pipe connections therebetween. There is a brake pipe and a connection between the brake pipe and the ABDW valve. Truck mounted brake cylinders are located at each truck and a brake cylinder pipe connects the brake cylinders with the ABDW valve. A brake cylinder pressure maintaining valve is connected to the brake pipe, brake cylinder pipe and volume reservoir, as well as to the emergency reservoir. The brake cylinder pressure maintaining valve operates to provide air from the volume reservoir to the brake cylinder pipe and thus the brake cylinders when pressure in the brake cylinder pipe drops below a predetermined level, thus insuring a minimum brake application pressure, regardless of the piston travel of the brake cylinders.

Abstract: A fluid system for the rail brake cyclinder of a highway/rail vehicle including a control valve responsive to brake pipe pressure drops to provide a control signal to a variable load relay valve assembly which provides brake cylinder pressures. The relay valve assembly maintains the rail brakes deactivated in the highway mode, provides braking pressure independent of the variable load portion for low pressure in the control valve's auxiliary reservoir, maintains a rail reservoir and rail suspension supply changed from the highway and rail supply lines, and creates an emergency condition in the brake pipe for low rail supply line and or rail reservoir pressure.

Abstract: Brake apparatus for a railway vehicle including a brake cylinder device of the type having a pair of interconnected pistons of unequal size to which the vehicle brake rigging is connected. The larger power piston forms an application chamber and a release chamber on its opposite sides in which air is stored for use in controlling the vehicle brakes. The brake apparatus further includes a control valve device that is operative responsive to a reduction of brake pipe pressure to conduct flow of air from the release chamber to a positioning chamber formed on the side of the smaller positioning piston corresponding to the side of the power piston having the application chamber, to effect movement of the interconnected pistons to a brake application position.

Abstract: Brake apparatus for a railway vehicle including a brake cylinder device of the type having a pair of interconnected pistons of unequal size to which the vehicle braking rigging is connected, the larger piston having first and second chambers formed on its opposite sides in which air is stored for use in controlling the vehicle brakes, and a control valve device that is operative responsive to a reduction of brake pipe pressure to transfer air from the first chamber to a third chamber formed on the side of the smaller piston corresponding to the side of the larger piston having the second chamber, to effect movement of the interconnected pistons to a brake application position. As piston displacement occurs, pressure in the second chamber is equalized with the pressure in the third chamber so that no pressure differential is developed across the larger piston, until a predetermined pressure is established in the third chamber consistent with a desired minimum brake application force.

Abstract: A railway vehicle brake apparatus including a brake control valve device having a service piston valve device operative responsive to a reduction of pressure in the train brake pipe to connect fluid pressure from the auxiliary reservoir to a brake cylinder device to provide a service brake application, and a high pressure spool valve device operative responsive to said reductions of brake pipe pressure exceeding a certain chosen rate to connect fluid pressure from the emergency reservoir to the brake cylinder device in parallel with the auxiliary reservoir pressure connected thereto from said service piston valve device to provide a higher emergency brake application pressure, there being arranged a cut-off valve device between the high pressure spool valve device and brake cylinder device which interrupts the flow of emergency reservoir pressure thereto until the auxiliary reservoir pressure supplied to the brake cylinder device is reduced to a predetermined level and a one-way check valve between the servic

Abstract: A brake control valve device for a railway vehicle having a service valve piston assembly subject to a pressure differential between the brake pipe and a single reservoir acting on a first piston and to brake cylinder delivery pressure acting on a second piston of the assembly. A brake pipe reduction actuates the service valve assembly, toward service application position, in which position, the single reservoir pressure is connected to a pilot chamber of a brake cylinder exhaust control valve for actuating a brake cylinder exhaust valve to its closed position, while concurrently, connecting the single reservoir pressure to the car brake cylinders. Pressure limiting means is provided to assure that sufficient pressure remains in the single reservoir following a full service or overreduction application for the purpose of providing additional braking pressure during 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.

Abstract: An emergency valve device for a direct release triple valve for use in braking systems is proposed and which for rates of fall of brake pipe pressure below a given rate permits a discharge via a restriction to atmosphere of quick action chamber reference pressure but for higher rates this discharge cannot keep up with the rate of fall of brake pipe pressure and the valve device moves further cutting off the restriction and produces a servo action to operate a vent valve connected to the brake pipe and produce an emergency application by connecting the emergency reservoir to the brake cylinders.

Abstract: A brake control valve device operated by a reduction in brake pipe pressure on one side of a movable abutment relative to control reservoir pressure on the opposite side embodies in the abutment a control reservoir charging valve mechanism, a filter and a choke arranged in series. The valve mechanism comprises a spring-biased valve slidably mounted in a ported bushing carried by the abutment. Two spaced-apart stops carried on the abutment enable relative movement between the abutment and the valve whereby, in one position of the valve, fluid under pressure may flow from the brake pipe to the control reservoir to effect charging thereof via the ported bushing, a passageway in the valve and the choke, and, in a second position of this valve, this charging communication is closed.

Abstract: A service valve portion of a railway vehicle brake control valve device embodies large capacity spool-type brake cylinder application and release piston valves and a small spool-type valve for controlling the supply and release of fluid under pressure to and from the application and release piston valves and also the reservoir charging and quick service features.