I worked at an American Can plant back in my college days (1960's). Besides the coils in Gons and Boxcars for cans, you'd have a boxcar every so often full of drums of solvents, paints, inks. I shudder to think of how we washed our hand in toluene, MEK and other carcinogenics.
the inside surfaces of cans were coated with a varnish like material. Some cans had labels printed on them instead of paper labels.
I don't recall any tank cars but, hey, it's your railroad.
Coils could also be chained to flat cars.