The Norfolk Southern Railway (reporting mark NS) is a Class I railroad in the United States. With headquarters in Norfolk, Virginia, the company operates 21,500 route miles in 22 eastern states, the District of Columbia, and has rights in Canada from Buffalo to Toronto and over the Albany to Montréal route. NS is responsible for maintaining 26,300 miles, with the remainder being operated under trackage rights from other parties responsible for maintenance. The most common commodity hauled on the railroad is coal from mines in Indiana, Kentucky, Pennsylvania, Tennessee, Virginia, and West Virginia. The railroad also offers the largest intermodal network in eastern North America. NS is a major transporter of domestic and export coal. The railroad's major sources of the mineral are located in: Pennsylvania's Cambria and Indiana counties, as well as the Monongahela Valley; West Virginia; and the Appalachia regions of Virginia, Kentucky, and Tennessee. In Pennsylvania, NS also receives coal through interchange with R.J. Corman Railroad/Pennsylvania Lines at Cresson, Pennsylvania, originating in the "Clearfield Cluster". NS's export of West Virginia bituminous coal begins transport on portions of the well-engineered former Virginian Railway and the former N&W double-tracked line in Eastern Virginia to its Lambert's Point coal pier on Hampton Roads at Norfolk. Coal transported by NS is thus exported to steel mills and power plants around the world.