This loco is roughly based on an Aveling and Porter 2-2-0 tram loco; specifially, "Blue Circle", which has changed ownership and location many times. A photo of one of the originals is shown on the left at the bottom. This lookalike was built up using parts from a variety of sources. The boiler, firebox and smokebox are from a Mamod TE1A, the wheels are from a Hornby Rocket, some of the mechanical parts are Meccano, the frames and buffer beams were scratch built.
The burner is a vapourising meths type, modified from a third party replacement for the standard Mamod one. It is located in a firebox from a Mamod TE1A, modified to provide bearings for the Meccano rear axle. The boiler is a standard TE1A boiler, 1 3/4" diameter x 6" overall length (somewhat shorter internally).
The engine itself is a standard TE1A reversible oscillating cylinder - single acting. Cylinder dimensions are 5/16" bore x 3/4" stroke. A belt is taken from the pulley on the flywheel to an intermediate double pulley (taken from a Mamod SW1 steam wagon). A second belt goes from the intermediate pulley to a 3" diameter Meccano pulley on the rear axle. This arrangement gives considerably more speed reduction than the TE1; more, even, than the SW1. This gives a more realistic scale speed when running.
A pair of scratch built frames extend the whole length, supporting the front axle, firebox, intermediate pulley and the front and rear buffer beams. The buffers and hooks are also built up from bits and pieces from the scrap box.
For size comparison, one of the photos on the left shows the engine sitting next to the Hornby Rocket, which has the same track gauge (3.5"). Photos and a description of the build project can be seen here