I have a thing for the very early PS2 steam locos with the die cast metal coal loads. I thought I struck it rich with a Rail King NYC Mohawk buy on eBay. The condition was pristine with almost no run time. The 9v battery was dead so I got a BCR from J&W Electronics. The head lamp was bad. No big deal, I can replace that. But man oh man did this thing smoke! Was shooting a video to share with a friend when fire started shooting out of the stack. Very impressive but not good. Long story short there is a lengthy thread from way back that discusses this issue. I measured a full 24 vdc to the smoke unit and the head lamp. The parallel 16 ohm resistors make 8 ohms so 24x24/8 = 72 watts when it should be less than 10. And yes, smoke fluid is an oil and if you get it hot enough the vapor will ignite. I tried a factory reset, no luck. My best guess is that the prior owner decided to shorten the python cable by pulling most of it inside the tender and maybe damaged a wire.
I found an LED that can handle the 24 volts so I now have a head lamp. My plan for the smoke unit is to get a 16 ohm power resistor, add that in series with the smoke unit and sink it to the chassis. If the 24 volts holds I'll get 1 amp through the smoke unit resistors and 8 watts. Does this sound sensible or am I about to do something dumb?