OK, now that we've got that cleared up -
I think you're ready to move up to a better-quality box car. The grafitti "tagging" is very good, but kind of wasted on that old Tyco/Mantua with truck-mounted horn-hooks. Of course, if you just used old cars to practice on, that's a good system, too.
Or, maybe you should weather the car before you tag it.
It takes an iron man to play with a toy iron horse.