This charming little loco was made by Bar Knight in Glasgow, a company that still exists doing precision engineering but (sadly) nothing to do with toys. It is an 0 gauge 2-2-0 loco, though obviously intended to represent an 0-4-0. The wheels have very large flanges so that it's unlikely to run on anything other than old fashioned tin-plate track. Identifying the model number of this engine is not easy. There were several similar models and the design of each changed in time. However, but I think it's a No 25 S from around 1926 or 27.
The simple pot boiler is 4" long x 1 3/8" diameter. It sports a safety valve and a dummy chimney. It is fired by a 3 wick meths burner, the tank for which is located under the cab. Steam is fed from the bottom of the boiler to a cross-pipe feeding the two cylinder port faces. There is an oil reservoir near the front end of the boiler feeding to the same cross-pipe. (Despite appearances, the oiler is original.)
There are two single acting oscillating cylinders, 5/16" bore x 9/16" stroke, directly coupled to crank pins on the rear wheels. Exhaust steam escapes directly into the atmosphere underneath the engine, with no attempt to direct it to the chimney.
As acquired, the only obvious major problem was a missing pipe from the oiler. The oiler also had a countersink screw in place of the filler plug. The safety valve leaked badly. I have fixed these problems and the engine now runs reasonably well on blocks, but lacks power. The poor performance appears to be just a case of being worn out! However, it seems to run better each time I run it so, maybe, it just needs running in.