Yep, the Seaboard System was formed as a merger of the Family Lines roads (SCL, L&N, Clinchfield, and other small roads) in December 1982. The Family Lines was a marketing thing by separate railroads trying to appear as if they were a part of a larger system, i.e., for more efficient service, just like the Chessie System did, which itself was not a railroad (it consisted of the separately owned B&O, C&O, and WM).
Kiz's article that he linked to is mostly correct, but I take issue with one statement: "As the L&N itself disappeared into the Seaboard System in 1982 just a few years later the Seaboard itself would disappear into CSX Transportation." There is a lot of confusion as to the formation of CSX Transportation. Seaboard System was technically not merged into CSXT. The Seaboard's name was changed to CSX Transportation on July 1, 1986, and the other Chessie roads were later merged therein. If I recall correctly, the C&O was the last Chessie road flag to fall in 1987.
DFF
