Thanks for the replies:
The smoke unit is the powered A unit. The dummy smokes well.
Oil is not something I've considered. After all, what is smoke fluid if not "oily?"
I have tried jiggling the fan impeller up and down on its shaft with a tweezers . . . to no effect. There is no foreign matter gumming things up I can see.
Going to the Lionel web site leaves me with the feeling that, by the time I got this thing fixed with parts, shipped to me in Canada, I'd be out more than a hundred dollars. I don't see just replacing the motor as being an option? Seems it's the whole smoke unit or nothing?