The first common carrier railroad was theBaltimore and Ohio RailroadB&O,BO. It is also the oldest railroad in the United States opening for use in 1830. The various stores in Baltimore were eager to trade with settlers. In the beginning the railroad was located entirely in the state of Maryland.
Competition with the C&O Canal made it necessary for the B&O to build a bridge across the Potomac at Harpers Ferry VA. The line then continued from Virginia to areas close tot the North Branch Potomac River and then re-entered Maryland on its way to Cumberland. The railroad proved crucial to the Union Army's success during the Civil War.
Over time the B&O Lines became part of the CSX Transportation Network.