B&O Railroad Bridge is a 1910 swing bridge in the Grays Ferry neighborhood in Philadelphia, Pennsylvania that carries CSX Philadelphia Subdivision rail lines over the Schuylkill River. It is located upstream from the Passyunk Avenue Bridge. It is also known as CSXT's Schuylkill River Bridge.
In 1977, the Chessie System, then owner of the bridge, did engineering studies of the swing bridge mechanisms, and determined that extensive rehabilitation was needed. However, the project was placed on hold for decades, and, despite associated FRA violations and operational difficulties, was not revived by successor CSX Transportation until late 2003. Completion was planned for May, 2004. There were issues with rail traffic, controlled by CSX, and river traffic, with the US Coast Guard concerned with the fact that during construction the bridge cannot be opened.
The rehabilitation was completed on time in May 2004, including extensive work on the miter rails, which are mechanisms allowing for disconnecting the steel rails when the bridge is opened, and reconnecting the rails when the bridge is returned to rail traffic.