A nice example of one of Polly Engineering's "Polly I"s.
Silver soldered copper boiler, 90psi working pressure, feed by axle pump and injector with auxiliary hand pump in the side tank. Cast iron cylinders with slide valve cylinders actuated by Stephenson's valve gear with pole reverser in cab. Drain cocks lever operated from cab. Screw-down brake operating on rear wheels.
Length 24 inches