Yard tractor

A yard tractor, also called a terminal tractor, UTR (utility tractor rig), or tug master, is the dedicated low-speed vehicle that hauls container chassis, roll-trailers, and mafi trailers around a terminal yard and between the yard and the quay crane. It has a fifth-wheel coupling with an integral lift to raise the trailer kingpin without landing gear, a short wheelbase for tight turning, and is built for high-cycle, short-haul duty, not highway use. In RoRo and PCTC operations it moves mafi trailers carrying breakbulk and project cargo. It is the link between the ship-to-shore crane and the yard stack, and fleet availability sets the crane’s move rate.