Practice question

How should shut-off valves normally be positioned for air to reach the rear trailer in a set of doubles?

  1. Open at the rear of the lead trailer and closed at the rear of the last trailer
  2. Closed at the rear of every trailer
  3. Open only at the rear of the last trailer
  4. Removed from the trailer air system

Answer: A — Open at the rear of the lead trailer and closed at the rear of the last trailer

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