A Class 1 railroad is defined as any railroad with annual revenue of more than $504,803,294 (the 1992 threshold of $250 million, set by the ICC, adjusted for inflation). There are six Class 1 Railroads operating in the United States; BNSF, CSX, CN, CPKC, NS and UP. CSX was formed through the 1986 mergers of Chessie System and Seaboard System/ Family Lines, and continues to operate today across more than 21,000 miles of track in the Eastern United States.