A "Polly IV", the evergreen 0-6-0 tender engine from Polly's range - there must be one running at just about every club in the country by now. This one is in good order and goes well, it was running happily outside most of the afternoon earlier in the week, there's a clip of it here.
Silver soldered copper boiler, 90psi working pressure, feed by injector and axle pump with auxiliary hand pump in the tender. Whistle mounted underneath cab floor. Cast iron cylinders with slide valves actuated by Stephenson's gear with screw reverser in the cab. Mechanical lubricator.