What are the color variations of this stock car? I am aware of red, green and yellow. Any others?
Gilbert made MoPac stock cars in red and in maroon. Some were painted, some were unpainted plastic. Some were open slat sides, some were closed slat.
Gilbert also made UP stock cars in yellow/silver and the NP Pig Palace in red/silver.
Lionel has subsequently made S gauge AF stock cars in CP Rail, red/white; UP, red/silver; GN, blue; REA, green/red and AFL, blue/yellow. A horse car, 41010, was made in green. There may be more new road names in recent catalogs.
I have seen red and green. A seller currently has a yellow for sale.
The green and yellow have been pricey...
I have some of the K-Line kits which were made from the Marx molds (1956) and 1985 K-Line production...and I will be painting and lettering for Mopac.
Marx made a zillion red ones and a few yellow, orange, and green ones, each of which apparently command a pretty premium.
The Marx plastic cattle cars with closed slats will work for S gauge. So will the stamped steel, lithographed Marx 3/16 " "scale" cattle cars.
The plastic Marx/K-Line cattle cars with open slats are too large for S gauge, unless you really are not fussy about scale.