A railroad car float or rail barge is a specialised form of lighter with railway tracks mounted on its deck used to move rolling stock across water obstacles, or to locations they could not otherwise go. An unpowered barge, it is towed by a tugboat or pushed by a towboat. This is distinguished from a train ferry, which is self-powered. Historical operations U.S. East Coast During the Civil War, Union general Herman Haupt, a civil engineer, used huge barges fitted with tracks to enable military trains to cross the Rappahannock River in support of the Army of the Potomac. Beginning in the 1830s, the Baltimore and Ohio Railroad (B&O) operated a car float across the Potomac River, just south of Washington, D.C., between Shepherds Landing on the east shore, and Alexandria, Virginia on the west. The ferry operation ended in 1906. The B&O operated a car float across the Baltimore Inner Harbor until the mid-1890s. It connected trains from Philadelphia to Washington, D.C. and points to the west. The operation ended after the opening of the Baltimore Belt Line in 1895. The Port of New York and New Jersey had many car float operations, which lost ground to the post-World War II expansion of trucking, but held out until the rise of containerization in the 1970s. These car floats operated between the Class 1 railroads terminals on the west bank of Hudson River in Hudson County, New Jersey and the numerous online and offline terminals located in Brooklyn, Queens, Staten Island, the Bronx, and Manhattan. Class 1 railroads in the New York Harbor area providing car float services were: Baltimore and Ohio Railroad Bay Coast Railroad Central Railroad of New Jersey Delaware, Lackawanna and Western Railroad Erie Railroad and Erie Lackawanna Railroad Lehigh Valley Railroad Long Island Rail Road New York Central Railroad New York, New Haven and Hartford Railroad Pennsylvania Railroad Reading Railroad As well as the offline terminal railroads: Brooklyn Eastern District Terminal Bush Terminal/Industry City Brooklyn Army Terminal Hoboken Manufacturers Railroad Jay Street Connecting Railroad New York Dock Railway Pouch Terminal East Jersey Railroad and Terminal Co. Car float service was also provided to many pier stations and waterfront warehouse facilities (that did not engage in car floating service directly) by the above-mentioned railroads. At their peak, the railroads had 3,400 employees operating small fleets totalling 323 car floats, plus 1,094 other barges, towed by 150 tugboats