The Baltimore and Ohio Railroad was the first common carrier railroad and the oldest railroad in the United States, with its first section opening in 1830. The B&O was the first company to operate a locomotive built in America, with the "Tom Thumb" in 1829. It is now part of the CSX Transportation (CSX) network, and includes the oldest operational railroad bridge in the USA. The B&O railroad served as the funeral train for Abraham Lincoln. At first this railroad was located entirely in the state of Maryland, with an original line built from the port of Baltimore west to Sandy Hook. In railroading's golden age, the B&O was one of several trunk lines uniting the northeast quadrant of the United States into a wide industrial zone. At the end of 1970, the B&O operated 5,552 miles of road and 10,449 miles of track, not including the Staten Island Rapid Transit or the Reading and its subsidiaries. The initial tracks were built with granite stringers topped by strap iron rails. In 1843, Congress appropriated $30,000 for construction of an experimental 38-mile telegraph line between Washington, D.C., and Baltimore along the B&O's right-of-way. Unsure exactly which materials would suffice, the B&O erred on the side of sturdiness and built many of its early structures of granite. The B&O was instrumental in supporting the Federal government during the Civil War, as it was the main rail connection between Washington, D.C., and the northern states.