Thanks again Ike and all for the very good information.
I am coming to believe that these cars likely were in service “demand” – i.e., were needed for their original use until at least 1975, and likely the early ‘80’s.
This is based on the idea that US Steel’s Venezuelan iron ore was available and in demand through that time period, even after nationalization of the US Steel and Bethlehem properties in 1975, as the government gave contracts to both companies extending at least until 1981.
Certainly Birmingham’s red ore sources were gone: US Steel/TCI closed red ore mines in June, 1962, and even Woodward closed their deep mine in 1972.
I’m learning about Taconite and how it came to Birmingham. It was being brought in by barge in the early 2000’s and later. At some point, it seems that Taconite pellets would have overcome the Venezuelan ore, based on transportation costs.
More ideas and info are always welcome, thanks again for the help
John R Stewart