On May 1,1984, as part of a restructuring program, United States Steel Corporation eliminated the Rail Transportation Department and turned its former in-plant transportation functions over to a newly formed BSRR operating subsidiary called the Fairfield Southern Company. Its duties include handling the Fairfield Works' inbound raw materials and outbound empties, making in-plant steel and scrap movements, moving "hot metal" between the blast furnace and "Q-BOP" (Basic Oxygen Process) and moving furnace waste to a dump site at Exum. The Fairfield Southern also hauls coal, mined at the United States Steel Corporation Oak Grove mine, from a coal washing and loading facility at Concord (near Hueytown) to the BSRR at Norrell Junction. While most United States Steel Corporation coal is exported through Port Birmingham, some tonnage finds its way to area power plants or coke making facilities. The Fairfield Southern also moves granulated coal, which reduces the need for natural gas and coke, from the Concord washer to the granulated coal injection facility at the Fairfield blast furnace.

The Fairfield Southern is not an actual railroad. All motive power and most rolling stock is owned and maintained by the BSRR. Trackage within limits of the Fairfield Works is owned by U.S. Steel and maintained by an outside contractor. Fairfield Southern employees operate under BSRR supervision. However, due to the nature of their work, they are covered by United Steelworkers of America agreements.