BC Transit – Air Brake Course

Charging the Trailer Reservoir
When trailer supply valve is opened, reservoir air from the tractor is
allowed to flow through a line into the tractor protection valve. The air
flows freely through the tractor protection valve, along the supply line,
through the one-way check valve in the emergency relay valve and into the
trailer reservoir. At this point the trailer brakes are released, and the unit
is ready to go.
Left click to begin animation
148