This is a 4mm:1ft (OO-scale) chassis for my Southern Diagramme 3105 plastic-bodied luggage van, British Rail PMV. You will require wheels on axles which are 26mm over pinpoints, chosen for your track gauge (e.g. OO/HO, EM or P4) and detailing parts which are also available (footsteps, buffers, brake linkage safety loops, brake handwheels, and brake blocks in pairs for each wheel (they fit from above, through holes in the floor). The body is also available, either as a single-piece, or separate sides/ends and roof. The chassis is LONGER than the body, because the van shock-absorbing by allowing limited sprung travel back and forth along the chassis. You will need to glue the body on centrally. You could try to mount it with some sort of spring and weight arrangement it to give a realistic shock-absorbing movement, but expectation should be managed.