Originally it had no smoke or flywheel. There were some guys adding both when I got mine so I had it upgraded. Would a Pittman be a drop in or require some skills whereas I have none?
It would fit no problem. I think you just have drill a couple new mounting holes and maybe drill the coupling out to 4mm. Lionel has flywheels for Pittmans.
Far right is a Mabuchi 550, next to it is a Pittman 9344. A Pittman 9334 is the same diameter and length as the Mabuchi.