A system for maintaining brake cylinder pressure includes a brake cylinder passage configured to be in fluid communication with a brake cylinder, a brake pipe passage configured to be in fluid communication with a brake pipe and a brake cylinder, a first valve member moveable between a first position and a second position, and a second valve member in fluid communication with a reference pressure. The second valve member is configured to move the first valve member from the first position to the second position based on a differential between a pressure within the brake cylinder passage and the reference pressure, where the brake pipe passage is configured to only supply air from a brake pipe to a brake cylinder when the first valve member is in the second position.

A system for maintaining brake cylinder pressure includes a brake cylinder passage configured to be in fluid communication with a brake cylinder, a brake pipe passage configured to be in fluid communication with a brake pipe and a brake cylinder, a first valve member moveable between a first position and a second position, and a second valve member in fluid communication with a reference pressure. The second valve member is configured to move the first valve member from the first position to the second position based on a differential between a pressure within the brake cylinder passage and the reference pressure, where the brake pipe passage is configured to only supply air from a brake pipe to a brake cylinder when the first valve member is in the second position.

A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal.

A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal.

A distributor valve for a brake control system of a railway vehicle is provided with an access interface that includes a plurality of access ports for measuring the operational pressures of the distributor valve. The distributor valve includes a pipe bracket and a main line and main portions mounted on the pipe bracket. The pipe bracket includes a plurality of passages for communicating the main portion and the main line portion with each other and with a brake pipe, brake cylinder, and reservoir of the brake control system. The plurality of access ports of the access interface includes ports in communication with the working chamber passage, valve chamber passage, brake pipe passage, reservoir passage, and the brake cylinder passage of the pipe bracket.

A parking brake apparatus is provided for an autonomously drivable vehicle having components of a parking brake system for applying a parking brake. The parking brake apparatus comprises a first controller arranged to provide one or more control signals to be applied to components of the parking brake system to apply the parking brake in response to a signal requesting the parking brake to be applied. The parking brake apparatus also comprises a second controller arranged to provide one or more control signals to be applied to other components of the parking brake system to apply the parking brake in response to unavailability of the first controller to cause the parking brake to be applied.

A parking brake apparatus is provided for an autonomously drivable vehicle having components of a parking brake system for applying a parking brake. The parking brake apparatus comprises a first controller arranged to provide one or more control signals to be applied to components of the parking brake system to apply the parking brake in response to a signal requesting the parking brake to be applied. The parking brake apparatus also comprises a second controller arranged to provide one or more control signals to be applied to other components of the parking brake system to apply the parking brake in response to unavailability of the first controller to cause the parking brake to be applied.

A control valve (3) of a compressed air system of a vehicle has a control piston (22), guided in an axially movable manner in a housing cylinder (25), two pressure chambers (32, 34) separated from one another by the control piston (22), which is sealed by at least one sealing ring (37) arranged on the outer circumference of the control piston (22). The sealing ring (37) is a radial sealing ring having an axial length which substantially corresponds to the axial thickness of the control piston (22). The sealing ring (37) has, on each of the two axial edges thereof, one respective radially obliquely outwardly directed sealing lip (39, 40) which is in contact with the inner wall (38) of the cylinder (25), and that a plurality of guide members (50) distributed over the circumference and formed between the two sealing lips (39, 40) on the sealing ring (37).

A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A tractor protection module delivers the pneumatic fluid at the control module delivery pressure based on a trailer park brake pressure of the pneumatic fluid.

A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A tractor protection module delivers the pneumatic fluid at the control module delivery pressure based on a trailer park brake pressure of the pneumatic fluid.