Roger Curtis’

MINNIE TRACTION ENGINE

There has been a trend in recent years for model engineers to build larger traction engines that perform well in a field. For model engineers with a typical workshop, building such large pieces is not possible. Smaller designs such as the Allchin Royal Chester by Bill Hughes and some of John Haining designs are within the scope of more workshops. But the one design which can be built in the small workshop with a 3.5” lathe, with much of it capable of being fabricated to maintain costs at a reasonable level is the 1:12 scale Minnie. Designed by Roy Mason it is truly a classic, built in large numbers around the world. It is not difficult to see why, when looking at Roger Curtis’ fine example.

Minnie is, of course, a freelance design, giving builders the freedom to add their own twist. They have been produced in various guises - traction engines, rollers, showmens’ engines, etc. Double size versions are also popular. Meanwhile, it is the original design that retains popular status.

Len Mason wrote:

“Large scale traction engines are attractive to operate,they are not everyone’s most convenient size to build. Storage can be something of a problem, too.The Minnie scale is that much more convenient to handle and can he looked on as a ‘single-handed’ engine.

“The prospective builder confronted with a new design looks first at the flywheel and rear wheel diameters, mentally assessing his lathe capacity for turning these items. Even in 1:8 scale rear wheels of around 9in. dia. are something of a faceplate ‘wangle’ on the normal 3.5" lathe.”

He also said of Minnie: “This size is somewhat small to include every item of a definite prototype as a working feature; a working governor, for instance, would be ‘watch-making’ in the extreme, with a fair chance of it failing to be satisfactory when fitted. However, if one is prepared to forgo the pleasure of knowing that a full-size version of one’s own model actually exists, a free-lance I in. scale engine can still incorporate reasonably correct full-size practice.”