Yard tractor pool

A yard tractor pool is the shared fleet of terminal tractors, also called shunt or shuttle tractors, that haul container chassis or roll trailers between the quay cranes and the stacking yard, dispatched and tracked by the terminal operating system. Pooling the tractors rather than tying each to one crane lets the TOS assign the nearest free unit to each move, cutting idle running and matching tractor count to crane intensity across a shift. A diesel or battery-electric terminal tractor pulls one chassis carrying a 40-foot box or two 20-foot boxes at low yard speed. In automated terminals the AGV or shuttle carrier replaces the manned tractor on the seaside loop.