|Headquarters||Philadelphia (Broad Street Station)|
|Locale||Pennsylvania, Delaware, Maryland and Washington, D.C.|
|Dates of operation||1902–1976|
|Predecessor||Philadelphia, Wilmington and Baltimore Railroad|
Baltimore and Potomac Railroad
Pittsburgh, Cincinnati, Chicago and St. Louis Railroad
Conrail system (freight)
|Track gauge||4 ft 8+1⁄2 in (1,435 mm) standard gauge|
|Electrification||12 kV 25 Hz|
|Length||717 miles / 1,154 km|
The Philadelphia, Baltimore and Washington Railroad (PB&W) was a railroad that operated in Pennsylvania, Delaware, Maryland, and the District of Columbia in the 20th century, and was a key component of the Pennsylvania Railroad (PRR) system. Its 131-mile (211 km) main line ran between Philadelphia and Washington.: 228 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.: 226
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 717 miles (1,154 km) of road, including 9 miles (14 km) of trackage rights.: 226–227
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, the 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).: 122 
washington terminal company.