Burlington Northern Santa Fe Corporation (BNSF) is engaged primarily in the rail transportation business. The rail operations of BNSF Railway, the Company's principal operating subsidiary, comprise one of the largest railroad systems in the United States. Including first, second, third and fourth main tracks, yard tracks and sidings, the total BNSF Railway system, consisted of approximately 50,000 operated miles of track as of December 31, 2001, all of which are owned by or held under easement by BNSF Railway, except for approximately 8,300 miles operated under trackage rights agreements with other parties. In serving the Midwest, Pacific Northwest and the Western, Southwestern and Southeastern regions and ports of the country, BNSF Railway transports a wide range of products and commodities derived from manufacturing, agricultural, and natural resource industries.