Richmond, Fredericksburg and Potomac Railroad

The Richmond, Fredericksburg, and Potomac Railroad (reporting mark RFP) was a railroad in the U.S. state of Virginia, connecting Richmond to Washington, D.C. The track is now the RF&P Subdivision of the CSX Transportation system; the original corporation is no longer a railroad company.

The RF&P was a bridge line, with a slogan of "Linking North & South," on a system that stretched about 113 miles (182 km). Until around 1965, the RF&P originated less than 5% of its freight tonnage, probably less than any other Class I railroad. For much of its existence, the RF&P connected with the Chesapeake and Ohio Railway, the Atlantic Coast Line Railroad, and the Seaboard Air Line Railroad at Richmond. At Alexandria and through trackage rights to Washington Union Station in Washington, D.C., it connected with the Pennsylvania Railroad, the Baltimore and Ohio Railroad, and the Southern Railway.

The rail line connected to the Washington and Old Dominion Railroad at Potomac Yard and interchanged with the Chesapeake and Ohio Railway at Doswell. Until 2024, it (along with the former Conrail properties) was the only CSX line to have cab signal requirements on its entire system; the railroad ended this practice on the line in June of that year in favor of positive train control.