Tug test and visual inspection are crucial to preventing a disconnect

While a tug test has always been crucial when hooking up a trailer, when hooking up multiple trailers, the tug test is even important for the rear trailer to avoid a disconnect. After the first trailer is hooked up, and after the dolly is connected to the first trailer, the operator then backs the dolly under the second trailer. It is at this time the dolly is freewheeling. The tug test should be done at this time, while the dolly is backed under the second trailer.

Once all air lines are attached to both trailers and air is flowing, when applying the brakes in the tractor, the operator is only tug testing the first trailer. Conducting a tug test while the dolly is initially backed under the second trailer ensures the driver is tug testing the rear trailer.

While tug tests are a crucial step to avoid a disconnect, the tug test is not the only step the manufacturer recommends when hooking up.

Remember:

The Trailer and Dolly Coupling page has resources available for service providers to ensure personnel are familiar with FedEx Ground equipment, including identifying the fifth wheel and ensuring that the fifth wheel and kingpin are securely locked, consistent with the DOT Regulations and the agreement provisions. Failure to properly install, operate or maintain the fifth wheel could result in tractor and trailer separation causing death or serious injury to others.