A fairly rare engine from the Stuart range, probably unsurprising given the complexity, this is their triple expansion marine engine. Cast iron cylinders with gunmetal slide valves actuated by Stephenson's reversing gear. It is fitted with feed and condensor vacuum pumps.
The engine has never been run on steam and is complete with a perspex display case. Fitted with cast iron piston rings, it is still slightly stiff to turn over by hand, although without tight spots.