Rail transit is the sum of commuter rail, heavy rail, and light rail. In several large urban areas, Amtrak and commuter rail stations are shared. Starting in 2001 stations serving the Alaska Railroad are included in the rail transit total.
Rail transit data for 2002 include service both directly operated and purchased. Prior to 2002, data only include directly operated service.
Amtrak, Amtrak Annual Report, Statistical Appendix (Washington, DC: Annual issues).
U.S. Department of Transportation, Federal Transit Administration, National Transit Database (Washington, DC: Annual issues), table 21 (for 2002 issue) and similar tables in earlier editions.