What font was used on the HO scale Spectrum Western Maryland 2-8-0? I would like to renumbered a loco.
WM Decal sets ought to already have the correct font.
I have a feeling you're trying to replace only one digit in a 3 or 4 digit road number. I've looked into that before with the Frisco decapod. A single digit from a decal set will certainly never match what's there. If it's not a minor variation in the font, it will be a minor variation in the height of the numeral, both resulting in a very visible mismatch.
If you replace all three, or maybe four, digits in the road number, they will all match. Think inside that box and you will have success.