Washington, Alexandria & Mount Vernon Railway Co. 1890 Alexandria & Fairfax Passenger Ry. Co. → 1892–1932 Washington, Alexandria & Mount Vernon Railway Co. Part of the Washington-Virginia Railway Co. in 1910–1927
Washington & Old Dominion Railway Co. 1900 Great Falls & Old Dominion Railroad Co. → 1912 Washington & Old Dominion Railway Co. → 1936 Washington & Old Dominion Railroad Co. Electric passenger service abandoned in 1941