Air Brake Coach
System partsQuestion 15 of 116

When do air tanks drain properly?

  1. While the compressor is running
  2. After the air pressure is gone and the contamination settles
  3. Only when the tank is full
  4. When the trailer is connected
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Correct answer: After the air pressure is gone and the contamination settles

Tanks do not drain properly until the air pressure is gone and the contamination settles and drips from the tank.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 3: Supply circuit, page 43

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Questions last reviewed: 18 October 2026