I think the NRM version was built on a Plymouth frame. I think I even remember seeing that manufacturer's name on a radiator inside the unit. In any case, even though it wasn't very convincing (smelled and sounded like a Greyhound Bus) the kids loved it when we had it at Steamtown.

We didn't actually run trains with it, instead we put it on the turntable on and off during the day and that worked quite well.

Dave Crosby

Here's a photo of the Powered Version of Thomas. Photo was taken July 18, 1999 at Abilene KS. The engine was self propelled, but lacked power to move much more than itself. The conversion covered over most of the air intake for the radiator, so it tended to run hot if worked for more than a few minutes.
Dan Rohrback