Just wanted to thank everyone who had offered comments on the "mystery car"
Over on the OSCALEMODELERS yahoo group, Jim Martin offered the following
From another list. The 2nd car is a OTDX gondola. It was used in the carbon
black / rubber industry. Sorry have no photo links.
Turns out that this is what I was looking for since my question was
originally prompted by a friend commenting that the car looked like the cars
"that we switched into the Uniroyal Plant in Opelika, Alabama, and were carrying
Thanks again for everyone's interest.