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more at http://quickfound.net/links/military_news_and_links.html Public domain film from the National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied. The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and equalization (the resulting sound, though not perfect, is far less noisy than the original). http://en.wikipedia.org/wiki/Armoured_vehicle-launched_bridge An armoured vehicle-launched bridge (AVLB) is a combat support vehicle, sometimes regarded as a subtype of combat engineering vehicle, designed to assist militaries in rapidly deploying tanks and other armoured fighting vehicles across rivers. The AVLB is usually a tracked vehicle converted from a tank chassis to carry a folding metal bridge instead of a turret. The AVLB's job is to allow armoured or infantry units to cross water, 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). The bridge layer unfolds and launches its cargo, providing a ready-made bridge across the obstacle in only minutes. Once the span has been put in place, the AVLB vehicle detaches from the bridge, and moves aside to allow traffic to pass. Once all of the vehicles have crossed, it crosses the bridge itself and reattaches to the bridge on the other side. It then retracts the span ready to move off again. A similar procedure can be employed to allow crossings of small chasms or similar obstructions. AVLBs can carry bridges of 60 feet (19 metres) or greater in length. By using a tank chassis, the bridge layer is able to cover the same terrain as main battle tanks, and the provision of armour allows them to operate even in the face of enemy fire. However, this is not a universal attribute: some exceptionally sturdy 6x6 or 8x8 truck chassis have lent themselves to bridge-layer applications... It was in the World War II era that the importance of armoured bridge layers, as well as combat engineering vehicles and armoured recovery vehicles, became fully clear. With the advent of Blitzkrieg warfare, whole divisions had to advance along with tanks, which were suddenly far out-pacing the speed of infantry soldiers. Besides leading to the advent of self-propelled artillery/assault guns, mobile anti-aircraft and armoured personnel carriers/cars, it became clear that functions like vehicle repair, mine-clearing, and the like would have to be carried out by armoured vehicles advancing along with tanks. Moreover, these forces would have to be able to cross all forms of terrain without losing speed, and without having to concentrate their thrusts over certain bridges (and the rising weight of armoured vehicles meant that fewer and fewer bridges could support these massed crossings). The only feasible solution to the dilemma posed by the mobility of all-mechanised armed forces was a dedicated platform that could improvise river and obstacle crossings at short notice and in otherwise inconvenient locations. Tracked and armoured, it was capable of operating right alongside combat units, crossing rough terrain and advancing in the face of light fire. To maximize on common parts and ease maintenance complications, they were usually based on existing tank chassis. One of the earliest series-produced examples is the Brückenleger IV, a German AVLB based on the Panzer IV, which entered service with the Wehrmacht in 1940. Twenty were built, but problems of excessive weight limited the vehicle's effectiveness, and eventually all 20 were converted back to tanks. A new scissors bridge design was brought out by the British in response to the war, sufficient to support a 24 ton load over 30 ft (9.1 m). This was developed for the Covenanter tank. Eventually, it developed into a 30 ton capacity and therefore was carried by a turretless Valentine tank. It was used in Italy, North West Europe and Burma. The Allies developed similar equipment, mostly based on the ubiquitous Churchill infantry tank (carrying the Small Box Girder) and the Sherman medium tank of the British and U.S. armies, respectively. In some early designs, bridge-layers could emplace bridges, but not retract them. Other vehicles were integral to the bridge themselves (such as the Churchill Ark), wading to the middle of a river or driving up against an obstacle and extending simple ramps in both directions; following vehicles would drive directly over the bridge layer...