Tichy O Scale railroad decal sets are great for lettering your own rolling stock. Waterslide-type decals should be cut just outside the printed area and then must be dipped in water until the decal film is loosened from the backing. They're best applied with small tweezers. Use your favorite decal film softening agent to make them snuggle down on the model surface while drying and overcoat with a clear spray sealer after they're dry.