How do you remove "pad printing" on a Bachmann passenger coach?

[:)]

I used brake fluid. I also had on hand a water soaked rag to neutralise the surface once the ink had gone.

Depending on how thick the paint is, I will even spot fluid onto the surface…but recommend the softly softly approach.
I also use this on my N scale stuff.
Just be very careful you don’t attack the base paint too much.