Chuck on Gscale train forum might well know. He does painting in UP colors. I'd post the direct link, but I think it's not allowed.
Maybe it was
Tru-Color UP Armour Yellow
I don't think posting links to users is a problem, just to commercial sites that aren't advertisers.
There's lots of Armour Yellow paint available, just not in spray cans.
American Flyer Union Pacific Armour Yellow 16-24. You can pick the sheen.
Website: My Perfect Color
Pretty Steep though. Two 11oZ Spray Cans come to $70 including the mandatory $30 Batch Production Fee.
Yep, a little steep! I actually found that one as well.
Train Enamel. com is the old Charles Wood paints. UP streamliner yellow. There are in Ohio, you can find them by Googling the name. They have rattle cans.
I found them, I don't quite understand their packaging.
What's a "fill Spray"?