DS499 was built about 1929/30 by a company called FWD. The company was absorbed about that time by AEC, they used AEC petrol engines. The original locomotives were based on the American FWD lorry chassis of WW1 but by the late 20's were entirely British made. Quite a few locomotives were built for industrial use, the Mumbles Tramway had one fitted with an overhead servicing tower. Most featured a radiator and bonnet at each end, the extra radiator was to aid cooling when running in reverse and the bonnet hiding the fuel tank.