Gray Silver I'm sure Scott got it right or we'll have to send them back for repainting.
My Milw Rd are gray.
Well, if someone would post a color photo of a real MR passenger car with gray trucks (and not just dirty silver), I would believe it is correct. Barring that happening, I think they should be silver.
Not sure if these show it.
https://www.american-rails.com/unst.html
https://www.antiquesnavigator....hicago-il--1971.html
The first photo is from 1960, and the passenger car trucks look to be dirty silver. The second photo is from 1971, and the trucks do look like they might be gray, so that is interesting. But the Olympian Hiawatha was discontinued in 1961 and the Olympian Hi super domes were sold to CN in 1962.
It seems that UP switched from gray to silver trucks on passenger cars in 1958, which is right after MR switched to UP colors, with the MR repaint to yellow occurring throughout 1957. Maybe UP liked the MR silver trucks look in 1957 and made the decision to switch the trucks on their own cars from gray to silver in 1958?
Anyway, I am with Erik in that I think that the MR Olympian Hi trucks were silver from the first repaint to UP yellow.