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Coupling and Uncoupling

Coupling and Uncoupling for doubles and triples is a required knowledge area under 49 CFR 383.115(a), covering the converter dolly and additional connections unique to pulling more than one trailer, drawn from 49 CFR 393.70(c) and (d).

Practice Coupling and Uncoupling

7 Questions

  1. Under 49 CFR 393.70(c), a full trailer must be equipped with a tow-bar and a means of attaching it. What does that paragraph require of the tow-bar and its attachment?
  2. A converter dolly is coupled to a trailer by a tow-bar, and the required safety device has to be attached to the towing vehicle. Under 49 CFR 393.70(d)(1), where may it not be attached?
  3. A full trailer towed by a tow-bar must have either two safety chains or cables, or a single chain or cable arranged as a bridle. Under 49 CFR 393.70(d)(6), what is different for a converter dolly with a solid tongue?
  4. You are coupling a set of doubles, and the second trailer has no spring brakes of its own. How should it be secured before you couple it?
  5. You are uncoupling a converter dolly from a set of doubles. Why must you never release the pintle hook while the dolly is still under the rear trailer?
  6. What is the correct order for coupling a triple-trailer rig?
  7. You are backing a converter dolly under the rear trailer of a set of doubles. What must be true of that trailer's height before the dolly goes under it?