As I mentioned here: https://ogrforum.com/t...52#44510799583967152
The Lionel Polar Express Berkshire belonging to a chum of mine was behaving in a sluggish manner, so I brought it back to the shops of the Razorback Traction Co. for some diagnosis and repairs. After some cleaning and oiling, the Berk was back up to factory spec, much to my relief, as, based on my experiences with my own Berk, for all I knew the motor and driver axles had seized...
My chum uses a brand of "nice smelling" smoke oil in his locomotives, which is all very well and fine except:
The doggone stuff has literally stripped the paint from the inside of the Berk's shell...
And I suspect, but can't prove, that the vaporized fumes have contributed to its somewhat piebald appearance.
Incidentally, if your modern era steamer is puffing irregularly, have a look at the piston:
When I popped it open, the cross-piece was out and one of the ball bearing valves was rolling around freely, allowing smoke to seep out under the chassis.
Conclusion: I can't tell you what to run in your locomotive, but I'm sticking to Lionel's premium smoke fluid. It may not smell like roses, but it also doesn't strip paint...
Mitch