I'm not very enlighten when it comes to tanks cars. Where you referring to structural or cosmetic changes to back date the STCX to the late '40's?
I was talking about the '58 GATX scheme. By 1943 there were only 7 unrepainted STCX cars, so I would say that only the earliest '40s would be okay, and probably only pre-1940 is really credible for the STCX cars.
Tony Thompson Editor, Signature Press, Berkeley, CA