A pneumatic brake system that includes at least one pneumatic latching
valve; a single device, such as a solenoid, for providing momentary pilot
signals to pneumatic latching valve; a source of pressurized supply air
in communication with the pneumatic latching valve; a spring brake or
other pneumatic device in communication with the pneumatic latching
valve; and, optionally, an indicator device for monitoring and displaying
the state of the pneumatic latching valve. Upon receiving a first
momentary pilot signal the pneumatic latching valve changes from closed
to open and delivers pressurized air to the spring brake. Upon receiving
a second momentary pilot signal, the pneumatic latching valve changes
from open to closed and exhausts pressurized air from the spring brake to
the external environment. The valve remains "latched" in its current
state until the signaling device is energized and the next momentary
pilot signal is received.