This engine came to the Marx Show and Tell meeting at York in the fall of 2001. It is an English Lumar Special 350 floor toy engine and was brought from England by Bill and Shirley Marston. The body stamping is the same as the 3978 engine, which was used for freight and passenger sets, but outfitted as a floor toy. These are rather rare.
Apparently there is more than one version of this engine.
Now, the next time someone asks you if you have a 350 engine, remember to say "which one"!

(Courtesy of Bill Marston)