For me, rescuing and restoring a junker is one of the most satisfying parts of the hobby. I model 3R Scale, but the beauty of tinplate has its own appeal. Here is a 259E that I restored in Milwaukee colors. The steps are pretty basic and no airbrush required: Strip the old paint, steel wool, prime, bake, paint, bake. Polish the copper and brass with a Dremel, assemble, clear coat, bake. Paints are Train Enamel rattle cans from Charles Wood and Krylon. The "oven" is a cardboard box (safety note - I never set it to bake and walk away. It does not get too hot, but you never know . . .)
Very nicely done as the finished project looks great.
For your baking process, what wattage bulbs are you using and typically how long do you bake the painted items?