BC Transit – Air Brake Course

Section Six
Single Circuit Tractor Trailer Systems
By the end of this section the student will be able to understand:
•How the tractor and trailer brakes connect and work together
•The operation of the various valves and systems
•The operation of the safety devices incorporated into the system
•Emergency functions of the system
•How to diagnose some faults associated with the connection and
functioning of the trailer brakes
Note: Single circuit systems only are covered here. Dual air systems will
be dealt with later in the course. As such, the trailers depicted in this
section are NOT equipped with spring brakes.
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