I thought they were blue, but I know that my memory is far from perfect. This is why you can't necessarily trust the old slides, because the processing can vary the color.

Chessie's Vermilion Red-Orange vs. IHB's Tennessee Orange...

https://www.rrpicturearchives.net/showP ... id=3696997

Maybe somebody knows somebody who knows somebody who works there...

BTW guys, that's one of the "unproven methods" I utilized to help figure out what some of the codes for Enchantment Blue are. If it's the same color in the same picture...

As it turns out, Enchantment Blue is identical to the ATSF's freight blue color, General Motors WE5659...

https://paintref.com/cgi-bin/paintdetai ... ode=WE5659

GM WE5659 and DuPont 2063 are the same color.

The Santa Fe yellow and Chessie's Federal Yellow are apparently identical as well. DuPont K9590 is an exact color match for DuPont 373. General Motors WE5910 matches both...

https://paintref.com/cgi-bin/paintdetai ... ode=WE5910

Back to the orange, it seems to be mildly distorted in many photos appearing darker, redder, and more saturated then it really is. What exactly causes this I do not know but here's another pic of #7311 which seems to more accurately depict the color as we might see it...

https://www.rrpicturearchives.net/showP ... id=1648587

What do you know, I found one. This is an International Truck with a factory paint job that's around thirty years older. The quality of the images might be bit sketchy as well so please don't use them for any comparison purposes whatsoever but unfortunately, I can't prevent anyone from happening to have a couple windows open at the same time...

https://topclassiccarsforsale.com/inter ... -r110.html

The General Motors code for DuPont 24592 is WE5502...

https://paintref.com/cgi-bin/paintdetai ... ode=WE5502

So yeah, I think we should be good with the blue and yellow, Eric. The orange, maybe not quite yet although I think the odds still aren't too bad even with minor adjustments to the brightness and saturation levels of the fan deck picture...

Since you brought up the heritage unit, Paul, here's another with the yellow included as well...