Air Brake Coach
Spring brakesQuestion 21 of 116

At about what pressure does the brake lining start to drag on the drums as the park springs expand?

  1. 82 to 84 PSI
  2. 55 to 60 PSI
  3. 10 to 15 PSI
  4. 100 PSI
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Correct answer: 55 to 60 PSI

By the time the spring takes up the free play, pressure is 55 to 60 PSI (380 to 414 kPa). The lining then drags on the drum.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 5: Park circuit, page 58

Practice spring brakes

Questions last reviewed: 18 October 2026