This is a modern high capacity tank wagon, constructed on the "monobloc" principle. It is fitted with air brakes, and was originally fitted with a through vacuum pipe to run in a vacuum braked train. The 45 ton rating is the wagon gross weight, when loaded. The capacity is about 33 tons. Before the 1960s, tank wagons were referred to by their capacity, which is the case with all the other tank wagons at Bo'ness. The tank is fitted with gravity discharge.
Some vehicles of this type are still in traffic on the main line.
