A finely-built example of an LNER A3 to Don Young's "Doncaster" design. A rare model, unsurprising given that Don Young was ex-Doncaster Works drawing office and didn't short-change builders on the amount of detail they were getting.
Silver-soldered copper boiler with combustion chamber and superheaters, fed by twin injectors with auxiliary hand pump in tender. Three cylinders with piston valves, the outside pair actuated by Walschaert's valve gear, the middle one by the ingenious derived motion supplied by Gresley-Holcroft conjugated gear. Mechanical lubricator (with additional dummy Wakefield lubricators on running board), drain cocks cable operated from cab.
The engine runs well, the valve gear is accurately set and produces a lovely even torrent of beats from the three cylinders, even at modest(-ish!) speeds. As with the only other A3 I've owned (again a Don Young one, that time "Solario"), there is a large amount of power available with very little fuss, the boiler steams particularly freely.
The engine comes with a large amount of documentation, builder's notes and a complete set of drawings. There is a purpose-built stand which also doubles as a rolling road for test running, the whole thing is mounted on castors for ease of moving.
Locomotive 47 inches
Tender 28 inches
Weight approx 250 pounds