CDL Combination Vehicles TestCombination Vehicle Air BrakesMedium
You are connecting a second trailer to a combination vehicle using a converter dolly. After connecting the dolly to the lead trailer, what is the critical next step before connecting the second trailer to the dolly?
- AConnect the dolly's electrical cord to the lead trailer.
- BEnsure the dolly's landing gear is fully retracted.
- CVerify the safety chains are securely attached between the dolly and the lead trailer.
- DCheck that the dolly's spring brakes are applied.
Show answer & explanationAnswer & explanation
Correct answer: C. Verify the safety chains are securely attached between the dolly and the lead trailer.
Safety chains (or cables) are a crucial safety device to prevent the dolly from separating from the lead trailer in case of a hitch failure. They must be securely attached before coupling the second trailer.
Why the other options are wrong
- A. Electrical connections are important but secondary to the mechanical securement of the dolly to prevent separation.
- B. Landing gear is retracted after coupling the second trailer, but securing safety chains is an earlier, more critical safety step.
- D. The dolly's spring brakes would release once air pressure is supplied; checking they are applied is not the next critical step.
Converter Dolly Safety Chains
Safety chains or cables are essential connections between a converter dolly and the lead trailer to prevent separation in the event of a pintle hook or drawbar failure, ensuring the dolly remains attached.
- Required for all converter dollies.
- Must be securely attached and crossed.
- Prevents runaway dolly/trailer.
- Checked during coupling and pre-trip inspection.
Memory trick: Dolly's ready, but don't just dash, first secure the chains, a safety flash!