Found this on display in Demascus, Virginia alongside the Virginia Creeper Rail Trail.

I got to looking at this thing and found that at one time it was actually powered! There's an 8 cylinder "straight 8" inside the boiler which drives a differential under the cab floor. This is turn drives a set of heavy chains which spin the axles. The whole thing appears to have been built on top the front pony truck of a steam locomotive.

Only reference that I can find to its history is that some nearby defunct factory my have built it to switch cars on their property.