Air Brake Coach
TrailersQuestion 30 of 116

Which side of the trailer does the supply coupler normally connect to?

  1. The right (passenger) side
  2. The top
  3. The left (driver) side
  4. The side with the brake chambers
Show answer

Correct answer: The left (driver) side

The supply coupler normally connects to the left side. This is a convention, not a rule.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 6: Tractor and trailer circuits, page 62

Practice trailers

Questions last reviewed: 18 October 2026