Not sure old boy. I did see an advert somewhere for some sort of paint stripper for models, but jut nip down to Halfords and grab a can of brake fluid.
That'll do the job, but test first, using a small amount on a cotton bud or soft cloth, especially if it's for your choo-choos, as the bodies are sometimes made from ABS, or nylon-type material or similar, and the paint work can be screen-printed, rather than paint.
Not a problem as such, but too much fluid can cause a sticky mess which can be a b*gger to clean up, as the screen ink and ABS can clog together as it dissolves.
Using the fluid sparingly, with perhaps more than one application, should remove the decoration 'gently', avoiding most of the mess.