Smoke unit super hot

Vin, these have an AC regulator, and that's a common failure item.  It can fail shorted, which dumps around 40 watts into the smoke unit instead of the six or eight watts they normally run on.  That can melt the plastic shell in short order.

If the regulator has failed, they are no longer available from Lionel.  What I do in that case is convert the smoke unit into a non-regulator model by changing the resistor and wiring.

It'll be fine if you turn off the smoke switch, you just don't have smoke.

@gunrunnerjohn Thanks for the info.  Maybe I’ll try your fix someday but for now it’ll be running without smoke for the foreseeable future.  At least it’s safe to run.  Appreciate it!