When I was a kid riding the B&O back in the 50's and early 60's, a very similar sight would greet me as I passed through the steel mills near Pittsburgh. At night the ingots would glow red/orange in the dark, each one a little brighter than the one in front. It might have been my imagination, but I swear I could feel the heat through the glass.

Ingots of this shape are usually referred to as "slabs". This shape is the first stage of plate and other flat goods. These appear to be "top poured" from their frothy appearance.
More interesting though are the slab cars. They have inside bearings like most locomotive pony trucks. Steel mills have long reused rail equipment or portions thereof. I wonder if some old locos of about Civil War era sacrificed the wheelsets as they met their demise.