Unfortinatly we all see color slightly diferently and the only was to match is in person as computers vary even more. Last every batch of cars were slightly different when factory new or rebuilts because someone had to mix the color. Less than one drop can change the color compleatly in hobby type batches of 1oz.
I only paint with gloss, so my depth of knowledge on many available color choices might not run as deep as some.
I googled images of the Frisco boxcars, and there is a lot of variation from one yellow to another in the photographs. I cut/pasted swatches from several images, and there is too much variation to do more than offer some "close enough" advice.
I would start with about 1/4 ounce of Floquil Wisconsin Central Gold, then add drops of Model Master RAF Trainer Yellow until the color looked right to my eye. That should give you enough for two freight cars.
Again, these are gloss colours.
-Kevin
Living the dream.
Got yet another one for my Forum friends (and yes this has been asked at the Frisco forum): Does anyone have a good paint/mix for SLSF yellow? I was given the old MDC 9509 (which is being used as a base for one of the two cars I'm modeling) as a good match for the needed yellow. Unfortunately, I don't have a great starting point for the color. I'd prefer a mix with Humbrol and/or Model Master paints (Given this is a project for only two cars, I don't have to worry about matching later.)