Question

The service air line is attached to the:

Answers

Relay valves.

Supply line.

Emergency air line.

Steering wheel.

Explanation

The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.

This questions appears in the following tests:

New Hampshire Combination

New York Double

New York Combination

North Dakota Combination

West Virginia Combination

Wyoming Tank