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1 1/2 inch scale Allchin traction engine - stock code 1882

A well-made Allchin traction engine to the W.J.Hughes design for "Royal Chester". Widely-regarded as the first close-to-scale drawings produced for a model traction engine, Hughes had access to the full-size engine in the 1950s (an engine now in preservation) and produced a highly detailed design which remains extremely faithful to the original. Written up in the "Model Engineer", Hughes subsequently published the construction articles as a book which is still available.

Although often tackled by newcomers to model engineering attracted by its modest size, the design calls for a considerable amount of experience to build successfully, both in the ability to tackle complex individual parts and also to cope with the sheer quantity of bits - basically if it was on the original engine, it appears on the model. As a result of this, we see a good number of Allchins which are not all they could be(!).

This model was built in the early 1960s to a high standard by an talented engineer whose next engine, a 2 inch scale Fowler Showman's engine went on to take a silver medal at the Model Engineer Exhibition. It has only ever been run on air.

Copper boiler, feed by mechanical pump on the second shaft and injector. Three cock water gauge with blowdown, 0-120 psi pressure gauge. Two speed with differential and back axle-mounted winch. Mechanical lubricator for cylinder with drain cocks operated from footplate. Dummy displacement lubricator on cylinder block and governor.

The engine runs very well on air, with crisp exhaust beats and a good tickover in both directions.We have tested the boiler at 180 psi, twice the 90 psi working pressure. The boiler is structurally sound, with no leaks from tubes, tubeplate or firebox. There are two leaks at the top of the backhead flanged joint to the wrapper, which appear to be due to inadequate solder penetration. Some earlier attempt has been made to caulk with solder, but really the back of the engine requires dismantling to gain adequate access to seal them up - this work will need to be done before the engine is steamed.

Length 26 inches
Height 17 inches
Weight approx 80 pounds

scale 1 1/2 inch & smaller