Does the scout motor still run? Whats wrong with it? It's your railroad; build a yard critter.
If you run command only, Then maybe make an outdoor stationary flywheel engine(running or static)? Gasses, petrols?, steam? There were a lot of cool "stationary tractor motors". Use the rod reaching indoors to "power an industry". Maybe a leather belt drive instead? Remove a wheelset or just cover one set and frame with flat, riveted panels; i.e., an "big iron box" with dual flywheels(drivers), a few levers, dials, valves, and crooked stovepipe stack with dunce cap rain guard.
Sometimes smoke can be fitted up to non-smokers.
A tiny fan (they get real small; under 1"square)and it might serve as a structure's smoke. Or even static smoke if it drafts well without help.