Using heavy fishbelly side framing loads up to 50 tons could be carried, including many of the light tanks and infantry support vehicles. The wagons featured screw jacks under the headstocks, allowing heavy vehicles to be driven on from an end loading dock and tracked vehicles could easily cross from one wagon to the next, driving down the entire length of a train.
Being substantially built these vehicles continued in service after WW2. BR examples were used to convey heavy loads, including large steel fabrications and castings. The MoD retained many wagons for military use, with a small fleet being rebuilt and updated with modern bogies, fittings and air brakes in the 1980s.