The Tramp was a development from the Bristol Pullman. In 1919, Bristol designer Frank Barnwell entered discussions with the Royal Mail Steam Packet Company about the feasibility of flying boats. They had extensive knowledge about steam turbine and they suggested to use that method of propulsion. The Pullman was the most suited candidate testbed. Unfortunately the combination wasn't very succesful, as the frame could not handle the power of the turbines. Only 2 frames were built, but neither ever flew. Used as ground test rigs for several years. Photo from Bristol Aeroplane Company