Air Brake Coach
System failuresQuestion 43 of 116

Which brakes do not apply when the secondary circuit fails?

  1. The steering axle brakes
  2. The drive axle brakes
  3. The trailer brakes
  4. The park brakes
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Correct answer: The steering axle brakes

A secondary circuit failure is the one tractor failure that stops a service circuit from working. The steering axle brakes do not apply.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 7: System failures, page 70

Practice system failures

Questions last reviewed: 18 October 2026