Hi Guy
I was a wheel shop foreman at the Sac Wheel shops, both freight and diesel.
New wheels shipped in, were in boxcars and in long rows so that a fork lift with a special heavy duty single fork could unload wheels in short order four to five at a time. These were a rusty tarnish color.
Scrap wheels were loaded into dons via an automated overhead roller roller system and dropped into the dons by three chutes, wheels just slid down the chute and dropped into the dons, The wheel dons sides and bottoms were rather beat up. Most of these wheels were a grey to grimy blackish color and a few dark brown.
My suggestion of what to do with them are
Dons, Use the darker ones and load them any which way,
Box cars with open doors, leave enough room for a forklift to drive in and turn 90 degrees to slide its fork into the wheels.
Flat cars, for mounted wheels, tan new reconditioned and darker wheel sets to have the wheels to be pulled and mounted
Unloaded new wheels,(shop wheel storage area) glue them in single rows to size all of which should be a lighter rust color.
Make roller bearings out of plastic tubing for the roller brgs and glut to end of the pointy axles for flat car loads
My suggestion is not to cut the axles or ends, but to take a small pin punch and just tap the axles through the wheel, leaving the center hole.
Ribbed wheels can stay out on the road a long time, usually under captive cars that cannot be inter changed MOW and such. We even had RJ axles come in off the system in the *80s, that should have been pulled out of service after WWII, these were to be scrapped on first sight. There were still rib-back wheel sets then also LOL
Hope the above helps…John