Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

...The knobs are exactly the same as far as I can tell...

In that case, i would rate it as a 1950s engine, or at the latest a very early 1960īs.

I donīt think anyone has dated the switch from the round to the oval tag precisely, and the same goes for the early style pressure gauges and bakelite handles.
(Unfortunately the "guesstimates" iīve seen through the years, often has been suspiciously well fitted to the guesserīs own interests, in terms of making own collection/engine more intriguing...but guess that one easiest can see what one looks for.)