I remove the locomotive and tender shells and repaint them from two-tone gray to all-black, leaving the front of the boiler silver-gray. Then, I'll apply white versions of 3975's original decals, only I'll give it road no. 3985 instead. I am not yet sure if I should buy black wheels with white trim or try to repaint the existing ones.

As I said, I'm not sure if I should do this, so I wanted your opinions. If you think I should, just leave me some tips or advice on what all would need to be done. Thanks!!!

Hmmm, you can always use this as a way to explore if the UP had gone a different direction in the late steam era. Or perhaps the UP doesn't exit the great depression very healthy and they are bought by another road

As for repainting, so long as you have an airbrush, I'd say repaint instead of buying new drivers. (provided the drivers are in good condition and quartered correctly)

would i have to make sure not to get paint on the flanges? the wheels on the black locomotives are black with white trim, right?

nevermind; the wheels are all-black. i don't have an airbrush, though