letter & numbering of a 70 ton ballast hopper car

I have purchased 2 Morrison-knudsen 70 ton converted ballast car kits from Red caboose to use on my MoW train. I am wondering if there are any pictures or guides that I can use to do the lettering and numbering for these cars. I have looked online but cannot seem to find anything. can anyone tell me where I can find a picture or some directions on where to look.

Which railroad?

Have you tried googling images for :

ballast car

ballast hopper

mk ballast

Dave H.