I've had good luck with a good pencil eraser, solv-a-set and a few minutes.
brush on the solv-a-set, let it set a few seconds, then start rubbing the area that you want to remove.
Don't press overly hard. In a few scrubs you should start to see ink fading. Keep this up until the numbers are gone.
I just did this with an Atlas Standard vision caboose. Took the White NS logo and numbers off in about 15 minutes.
If the numbers are on a smooth surface with no ribs or rivet lines you shouldn't have anything left. If there are rivets or grooves like around doors, you might have to go in after the paint with a pointed tool, but not anything sharp like a knife point.
Just keep a close eye on the paint to make sure your no rubbing through the paint. You might want to try it on a old shell or somewhere it isn't visible.
Just take your time.
Hope this helps,
Allen...