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.

The railine connected to the Washington and Old Dominion Railroad at Potomac Yard and interchanged with the Chesapeake and Ohio Railway at Doswell.

It opened from Richmond to Hazel Run in 1836, to Fredericksburg on January 23, 1837, and the rest of the way to the Potomac River at Aquia Creek on September 30, 1842.

[3] Badly damaged during the Civil War, on October 11, 1870,[4] an extension to the north toward Quantico was authorized at a special meeting of the company's stockholders.

The railroad went bankrupt and was sold July 9, 1887, being reorganized November 23, 1887, as the Alexandria and Washington Railway.

In 1873 the Baltimore and Potomac Railroad's branch over the Long Bridge opened, giving a route into Washington, D.C., over which the A&W obtained trackage rights.

At Quantico the 1.7-mile (2.7 km) Potomac Railroad, chartered April 21, 1867, and opened May 1, 1872, connected the two lines.

[citation needed] As the link between "North and South" the RF&P primarily hosted the trains of other railroads, particularly those on the lucrative New York–Florida run.

[19] The section of the Blue Line parallels Virginia State Route 110 where passing Arlington National Cemetery.

The unit is designed with the cab staying in YN3C and the long hood being painted in the RF&P blue and grey.