CSX Corporation was formed in 1980 by the merger of Chessie System and Seaboard Coast Line, each of which was the product of many previous mergers. Component railroads included some of the greatest names in rail history such as Baltimore & Ohio, Chesapeake & Ohio, Atlantic Coast Line, Seaboard Air Line, and Louisville & Nashville, as well as Georgia Railroad, Clinchfield, the West Point Route, and others. The Baltimore & Ohio, chartered in 1827, was the country's oldest common carrier railroad; the Louisville & Nashville was one of the strongest railroads in the east, and the Atlantic Coast Line justifiably called itself the Standard Railroad of the South.
For legal reasons the Chessie and SCL railroads operated independently until 1986-87, during which time some rather confusing additional sub-mergers and name changes were made. In 1983, Seaboard Coast Line, Louisville & Nashville, Georgia Railroad, and the Clinchfield merged to become Seaboard System Railroad. Three years later, in 1986, Seaboard System changed its name to CSX Transportation. The Chessie's railroads, C&O, B&O, and Western Maryland, were not initially included in the merger, but the following year B&O was merged into C&O and, a few months later, the C&O was merged into CSX Transportation.
The name CSX is said to represent the merger by combining the first letters of Chessie and Seaboard along with an X to signify multiplying the combined strength of the two railroads. It must have worked because CSX is now one of the nation's largest railroad companies. In Georgia, like most of the eastern US, there are only two railroads of substantial size, CSX and Norfolk Southern.