The Philadelphia, Baltimore and Washington Railroad (PB&W) was a railroad that operated in Pennsylvania, Delaware, Maryland, and the District of Columbia from 1902 until 1976. A key component of the Pennsylvania Railroad (PRR) system, its main line ran between Philadelphia and Washington. The PB&W main line is now part of the Northeast Corridor, owned by Amtrak.
The railroad was formed in 1902 when the Pennsylvania Railroad merged two of its southern subsidiaries, the Philadelphia, Wilmington and Baltimore Railroad and the Baltimore and Potomac Railroad.
In 1907, the PB&W became a co-owner of the new Washington Terminal Company, which operated the new Washington Union Station, the marble structure dubbed the "Transportation Temple of America".
In 1916, the PB&W operated of road, including of trackage rights.
The PB&W acquired six railroad companies:
In 1928, the PRR began to electrify the main line between New York City and Washington, D.C., using catenary. Electrification of the PB&W portion was completed in 1935. Amtrak still uses the 25 Hz traction power system.
In 1968, Pennsylvania Railroad and its longtime rival New York Central Railroad merged to form the Penn Central Railroad. The PB&W remained a separate legal entity, although controlled and operated by the new company. The Penn Central declared bankruptcy in 1970 but continued to operate trains until 1976, when the company's railroad assets were sold under the Railroad Revitalization and Regulatory Reform Act. Under the new law, Congress authorized the sale of the PB&W right-of-way between Philadelphia and Washington, and related assets (such as the Washington Terminal Company), to Amtrak. Other PB&W assets, including almost all of the PCC&StL (Pan Handle), were sold to the new Consolidated Rail Corporation (Conrail).