These two cars represent a brand new (built in February of 2015) series of bulkhead flatcars operated by Essar Steel Algoma with their own reporting marks (ESAX). The first example above, ESAX 25, was photographed in the Huron Central yard in Sault Ste. Marie on July 12, 2015. Almost an entire track appeared to be filled with these empty cars.
The second example below, ESAX 38, was photographed with a load of steel in a westbound Canadian Pacific train at White River on July 15, 2015. Presumably this car (and several other steel loads, mostly coils, next to it) were interchanged from CN at Franz.