My first Doll engine, which is, I believe, a model 511/3 but I'm not 100% sure of that. It is of the type called "locomobile". This is a bit of a misnomer as it's not a loco and definitely not mobile! However, there may be a language ambiguity here. The boiler is a loco type.
The boiler is a locomotive type, with the firebox at one end and supported by a pillar at the other end and a dummy smokebox & chimney. There is a hole in the base intended for a round, wick-type meths burner, which is missing. The boiler is 195mm x 60mm diameter with the engine bracket mounted on top. It has a weighted safety valve (the original weight for which is missing), a separate filler plug, a U tube water level glass and a whistle mounted, unusually, on the end cap.
The steam feed is taken directly to the steam chest of the double acting fixed cylinder. There is no control of the steam, just a dummy governor. The cylinder is 16mm stroke. The bore is unknown as the cylinder is encased in an outer cover and I have not dismantled it. It has a slip eccentric piston valve. The crankshaft has the crank and eccentric inside the main bearings and has twin flywheels, 66mm diameter.
As acquired, there was surface rust on all the steel parts but, otherwise, cosmetic condition was fair. I have repainted the rusty parts. As is common with these things, the burner and weight for the safety valve are missing. I have cast a new weight, using a thimble as a mould. I have a non-original burner that fits, suitable for gel fuel. Also, I believe there should be a dummy spark arrestor on the chimney top.