Roundhouse Shorty Tank cars

What do/did those Roundhouse MDC 30’ Shorty Tank Car carry?
Do they still run?

Modern 30’ tankcars are extremely rare. The ones I have seen appeared to be carrying petroleum refining catalysts of some type. I think I have seen photographs of some carrying sulfuric acid and some carrying sodium hydroxide. The MDC tankcars have no specific prototype.

I will occasionally see an Ethyl Corportation 30’ tankcar with an underframe carrying tetraethyl lead.

Eric once again you come to my rescue in my mission to find short cars.
Thanks!

The shorty tank cars now are about 40 feet. They carry dense liquids, like molten sulfur, clay slurry, corn syrup, types of acid, and the like.

Nick