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Better yet look for internet pix of your locos to see how well they hold up to usage. If you have some Santa Fe books look at those pix. There should also be pix in the Yahoo Group "ATSF" & "Santa Fe" forums.
A Santa Fe loco right out of the paint shop would be painted the same blue as on the rest of the loco. If it's been out on the road a while it will look weathered. There might be some rust but only on a loco that hasn't been to the paint shop in a long while or is never going to one if it's up for retirement soon.
Although the plow would be the same as the pilot, if it had run in snow for any length of time, the paint would be rubbed off where the snow moved across it, and you would have "bare metal"..........after a while like that, the bare metal would turn rusty, but more snow would scour the rust off again.........come spring, the RR would likely repaint the plow to avoid heavy rust buildup. Keep that in mind, the color would depend on the time of year.
Bare metal rusts........the railroads will normally touch up the plows in late spring, so if you are running a "summer" layout, the plow would be painted, but during the winter, the plow would likely be silver (bare metal), rust, or some combination. So when I said "color" I was referring to the original color or a "weathered" gray or rust color. They don't change the painted color.