The military vehicles on the field had also the support of the engineers. These types of vehicles, called AVRE, or Armored Vehicle Royal Engineers, had the purpose of transporting and protecting a team of engineers, ready to intervene on the field tanks or fighters. One of the most common tasks they carried out was to replace the existent mounted weapons on a tank, with ones larger in caliber.
The first vehicle of this type was the Heavy RE tank, invented by Major Giffard Martel, right after the end of the World War I. Its mission was to offer bridging to other military tanks, in the difficult to reach areas and to clear the mines on the field. Between the first and the second World War, the bridging tank was improved significantly: it could expand up to 26 feet, thus cover bigger gaps. It was built on a system of wire ropes, made of steel, and mounted on a travelling jib. The minds behind these inventions were that of Captain Stewart and Delany, a civilian scientist.
At the beginning of the World War II, the vehicle had to be perfected and developed. It had the capability to sustain a load capability of 24 tons and span its width up to 30 feet. The vehicle served mostly for the Allied Forces, especially Czechoslovakia and Australia. Later, improvements made it possible for such a bridge vehicle to expand its bridge in 90 seconds and to a tracked capability between 40 and 60 tons.
Churchill ARK, which stands for Armored Ramp Carrier, is one of the most well-known vehicles in its class. The vehicle itself would expand and transform into the bridge, and also span in both vertical and horizontal axes. Both the front and the back of this model were equipped with ramps, which extended its lengths for the use in terrain difficult to navigate.