... we would use hot air blown in at 600C or plug in a heating element or whatever.
Indeed, any steam loco in use now probably should have at least an #ImmersionHeater retrofitted, and/or be filled up with hot water not cold.
Preferably _very_ hot water.

Steam locos go quite a way with the fire out, I assume drivers knew when to tell the fireman to take a rest, or cook lunch or whatever.

And they still go #Chuff! #Chuff which is essential and make clouds.

But we would like to keep it #hot.