The electro-pneumatic latching valve system having an electrical switch
unit that further includes an "apply" or "activate" switch, a "release"
or "deactivate" switch, and a power supply. A first solenoid valve is in
electrical communication with the activate switch and a second solenoid
valve is in electrical communication with the deactivate switch. A
pneumatic latching valve is in pneumatic communication with the first and
second solenoid valves and a source of pressurized control and supply air
is in pneumatic communication with the pneumatic latching valve and the
solenoid valves. A terminal device, e.g., a spring brake, is in pneumatic
communication with the latching valve, and the device is released or
applied in response to pressurized supply air delivered to the device
through the pneumatic latching valve in response to pneumatic control
signals delivered to the pneumatic latching valve from the solenoid
valves.