Air Brake Coach
System failuresQuestion 50 of 116

What happens if the trailer air lines are reversed on a spring brake trailer?

  1. The trailer brakes lock on every stop
  2. The compressor stops
  3. The tractor brakes fail
  4. The park brakes will not release
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Correct answer: The park brakes will not release

Reversed lines stop the park brakes from releasing on a spring brake trailer.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 7: System failures, page 73

Practice system failures

Questions last reviewed: 18 October 2026