A steam powered tank? I bet it was unbearable inside from the heat and leaking steam.

When a flame thrower was developed in 1917 the test was so successful a vehicle was needed to carry it. This is the result. Modelled on a British Mark IV tank design it was built and demonstrated in Boston in April 1918. The armament consisted of the flame thrower device and 4 machine guns. It was powered by steam engines so there must be also be a boiler onboard, maybe not the best thing to be standing next to if bullets are flying around. The weight was 50 tons, top speed 4 mph and offered no improvement over the internal combustion powered machine. Only one was built.