was abandoned shortly afterwards, and the North Shore Branch continued to carry freight. On September 7, 1954, SIRT applied to discontinue passenger service on the Tottenville Branch on October 7 of that year; a large city subsidy allowed passenger service on the branch to continue. In 1956, work began on the replacement of the Arthur Kill swing bridge by a single-track, vertical-lift bridge, which opened in August 1959. The prefabricated, 2,000-ton bridge was floated into place. The new bridge could rise and, since it aided navigation on Arthur Kill, the federal government assumed 90% of the project's $11 million cost. Freight trains started crossing the bridge when it opened on August 25, 1959. The Travis Branch was extended in 1958 to a new Consolidated Edison power plant in Travis (on the West Shore), allowing coal trains from West Virginia to serve the plant. Operation of the Tottenville line was turned over to the Staten Island Rapid Transit Operating Authority (a division of the state's Metropolitan Transportation Authority) on July 1, 1971, and the line was purchased by the city of New York. As part of the agreement, freight on the line would continue to be handled by the B&O under the Staten Island Railroad. The first six R44 cars (the same as the newest cars then in use on the subway lines in the other boroughs) were put into SIRT service on February 28, 1973, replacing the ME-1 cars which had been in service since 1925. Between 1971 and 1973, a project began to extend the high-level platforms at six stations. A station-rebuilding program began in 1985, and the line's R44s were overhauled starting in 1987. The B&O became part of the larger C&O system in a merger with the Chesapeake and Ohio Railway, and the island's freight operation was renamed the Staten Island Railroad Corporation in 1971. The B&O and C&O became isolated from their other properties in New Jersey and Staten Island with the creation of Conrail on April 1, 1976, in a merger of bankrupt lines in the northeastern U.S. Their freight service now terminated in Philadelphia, but for several years afterward B&O locomotives and one B&O freight train a day ran to Cranford Junction. In 1973, the Jersey Central's car float yard was closed; however, the B&O's car-float operation was later brought back to Staten Island at Saint George Yard, after having ended in September 1976.