2 1/2 inch scale Avery undermount traction engine

An unusual model of an American Avery undermount traction engine. The work of a prolific modeller (he also built, among other things, the Fowler DCC road engine we currently have in), this one started out inspired by a picture in a magazine.

In working up drawings, the builder was fortunate to make contact with a man in the States who lived 100 miles away from a preserved example and was more than happy to drive over to measure and photograph the full-size engine.

Technically interesting, it's very different to what we're used to in an English traction engine! There's a steel locomotive type boiler, set high on a girder frame, with a pair of cylinders working beneath. The two road speeds are engaged by separate dog clutches, one each end of the second shaft and driving through a differential to the back axle.

A big engine in full-size, this 2 1/2 inch scale model is nearly five feet long and weighs getting on for 400 pounds. I particularly like the steering which works through a reduction gearbox - very light to operate, smooth in operation.

Unused for some years, the boiler has some old club paperwork - the last certificate expired in August 2018. The engine runs, although there is some work to do by the builders own admission for running in reverse, when the weighshaft tends to tilt back into mid gear.