▚ The eastern merger
CSX was created in 1980 as a holding company combining the Chessie System (B&O, C&O, Western Maryland) with the Seaboard System (Seaboard Coast Line, L&N, Clinchfield and more). In 1986–87 the railroads were formally merged into CSX Transportation.
▚ Coal and Conrail
CSX became one of the two dominant eastern railroads, hauling Appalachian coal and, in 1999, splitting the old Conrail system with rival Norfolk Southern — gaining the water-level route to the northeast.
▚ On this layout
CSX runs here as modern EMD power — SD80MAC, SD70MAC, SD70ACe, SD70M, SD50, and SD40-2 — the diesel fleet of the modern eastern coal railroad.