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

Thanks, Charlie!  I'm glad you liked the website.

The pictures of the twin are recent.  The engine has been in the collection for 20 years and is the engine featured in Stilson's book. 

The only other twin I'm aware of was this one where the seller apparently didn't know what they had.  https://toysteamengine.net/vintage_steam_engine_toy_model_cast_iron_base_vertical_boiler.html  If that's not the one you now have, then there may be more of these than we thought.

I like the video, and will certainly take you up on your kind offer of a link.