A 3/4 inch scale Allchin agricultural engine, built from one of the well-regarded kits by Michael Holden of Banbury - long out of production, they made up into a well-detailed, nicely proportioned engine of a good size to display on a bookshelf.
This one is well put together, nicely painted and unsteamed from new - boiler is gas-fired.
scale | 1 1/2 inch & smaller |