The original purpose of this design was to carry steel plate, a traffic which declined as Britain abandoned its heavy engineering industries. This example was modified for use as a crane runner wagon by the railway Civil Engineer.
The modification added a trestle which takes the weight of the crane jib, and removed the side doors at one end to give access to a toolbox. The roller bearings are probably original.
This wagon ran with 5 ton capacity permanent way steam crane No.RS1034, which was constructed by George Russell & Co. Ltd. at Motherwell in 1938.