The depressed centre well was needed to keep the higher vehicles inside the restricted British loading gauge, but the wagons were built with sloping end ramps and bridge plates so vehicles could be driven along the length of a train for rapid loading and unloading.
Following the invasion many of these wagons were transferred to France to keep the advancing front line supplied with replacement armoured vehicles, which would often have a low maximum road speed.
After WW2 the Ministry of Defence retained a small fleet of these wagons for moving military vehicles, some being rebuilt in the late 1970s with modern bogies and air train brakes. The remainder were passed to British Railways ownership, being used as well wagons for high or heavy loads and in engineering service.
This model is finished as a wagon with the original diamond bogies and painted in British Railways bauxite brown livery. In service with the British Railways engineering departments this wagon was originally operated by the LMS, hence the DM series number.