Air Brake Coach
System failuresQuestion 48 of 116

What happens when the trailer emergency line ruptures?

  1. You lose all control of the trailer
  2. The trailer brakes work better
  3. Only the hand valve fails
  4. The governor cuts out
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Correct answer: You lose all control of the trailer

The tractor protection system should work and the trailer emergency brakes apply. Control of the trailer is lost.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 7: System failures, page 72

Practice system failures

Questions last reviewed: 18 October 2026