Penn Central MP 54 units, 1970s

The first still in Pennsylvania Railroad livery, the second in Penn Central colours at Washington Union Station in March 1978.  It was a very numerous type: 481 were built for the PRR; 923 for subsidiary Long Island Railroad and 18 for the Pennsylvania-Reading Seashore Lines. The class was initially constructed as an unpowered locomotive hauled coach for suburban operations, but were designed with the capacity to be rebuilt into self-propelled multiple units as electrification plans were realized. The first of these self-propelled cars were placed in service with the PRR subsidiary Long Island Rail Road with DC propulsion in 1908 and soon spread to the Philadelphia-based network of 11 kV AC electrified suburban lines in 1915. Eventually the cars came to be used throughout the railroad's electrified network from Washington, DC to New York City and Harrisburg, PA.

The cars ran in service with the PRR until the Penn Central merger in 1968 at which point they were already being marked for replacement by new technology railcars such as the Budd M1 and Pioneer III. After the bankruptcy of the Penn Central the remaining MP54's found themselves being operated by Conrail under contract with local commuter rail authorities. The last MP54 cars were retired in 1980-81 while engaged in Philadelphia suburban service.