The hot metal cars were built with a thick metal plate and were lined with firebrick. They were extremely heavy and difficult to maneuver.
The larger hot metal cars had 16-wheel trucks and if they were completely full could, weigh 400 tons.
Steel production in the United States peaked at 111.4 million tons in 1973, and declined slightly to 97.9 million tons in 1978. By 1984, steel production collapsed to just 70 million tons.