Armoured vehicle-launched bridge

An armoured vehicle-launched bridge (AVLB) is a combat support vehicle, sometimes regarded as a subtype of Military engineering vehicle, designed to assist militaries in rapidly deploying tanks and other armoured fighting vehicles across gap-type obstacles, such as (and primarily) rivers. The AVLB is usually a tracked vehicle converted from a tank chassis to carry a folding metal bridge instead of weapons. The AVLB's job is to allow armoured or infantry units to cross craters, anti-tank ditches, blown bridges, railroad cuts, canals, rivers and ravines), when a river too deep for vehicles to wade through is reached, and no bridge is conveniently located (or sufficiently sturdy, a substantial concern when moving 60-ton tanks).