the Richmond, Fredericksburg, and Potomac Railroad connected Richmond to a steamboat pier at Aquia Creek; the direct link to Washington DC was not built until 1872 (after the Civil War)
Source: Library of Congress, Chronological history of the Civil War in America and hand atlas of the slave states ("Virginia, Maryland, and Delaware" map by J. H. Colton, 1863)
the Richmond, Fredericksburg and Potomac Railroad was unable to block the Virginia Central from building a competing line between Richmond and Hanover Junction (modern Doswell)
Source: Library of Congress, Map showing from Richmond to Fredericksburg, Va (Robert Knox Sneden, 1864-65)
the Richmond, Fredericksburg and Potomac Railroad built its northern connection originally at Belle Plain but later switched to Aquia Landing, and the Union Army used Belle Plain as its primary supply point during the 1864 Overland Campaign
Source: Library of Congress, Map showing from Richmond to Fredericksburg, Va (Robert Knox Sneden, 1864-65)
to supply the 1864 Overland March, the Union Army constructed the Belle Plain landing rather than the old Aquia Landing steamship wharf
Source: Library of Congress, Fredericksburg to Petersburg, VA (by Robert Knox Sneden, c.1863)
the Richmond, Fredericksburg, and Potomac Railroad abandoned its line to Belle Plain landing at Potomac Creek, after building a direct line to Alexandria in 1872
Source: Library of Congress, Map of northern Virginia (1894)
in 1905, the tracks of the Richmond, Fredericksburg and Potomac (RF&P) Railroad still used Belvidere and Byrd streets
Source: Library of Congress, Sanborn Fire Insurance Map from Richmond, Independent Cities, Virginia (1905)
the railroad gap between Fredericksburg and Alexandria was finally closed in 1872
Source: Library of Congress, A map showing the Atlantic Mississippi & Ohio R.R. and its connections from Norfolk to Cumberland Gap via Bristol (1867)
The northern terminal of the original Richmond, Fredericsburg and Potomac Railroad (RF&P) was Aquia Landing. Until 1872, steamboats on the Potomac River carried passengers and cargo between Aquia Landing and Washington, DC.
The gap was closed in 1872. The Richmond, Fredericsburg and Potomac Railroad was extended north to Quantico, while the Alexandria and Fredericksburg Railway was constructed south from Alexandria to Quantico. At Quantico, the separate Potomac Railroad connected the two, closing the last two miles.
the Alexandria and Fredericksburg Railway connected with the Richmond, Fredericsburg and Potomac Railroad at Quantico in 1872
Source: Library of Congress, Virginia, Tennessee, and Georgia Air Line Railroad (1882)
the northern terminus of the Richmond, Fredericksburg & Potomac Railroad was Aquia Creek until 1872
Source: Library of Congress, A map of the internal improvements of Virginia (Claudius Crozet, 1848)
the Richmond, Fredericksburg & Potomac Railroad stopped at Aquia Creek before the Civil War
Source: David Rumsey Historical Map Collection, New Map Of Virginia (Henry S. Tanner, 1845)
Richmond, Fredericksburg & Potomac Railroad bridge over Potomac Creek, rebuilt in 1862 with what President Lincoln claimed were just "cornstalks and beanpoles"
Source: National Archives, Richmond, Fredericksburg, and Potomac Railroad's Potomac Creek Bridge after reconstruction (1882)