Wilkes Street Tunnel was part of the Orange and Alexandria Railroad, founded in 1848 to promote trade with western Virginia. The railroad inaugurated its track in Alexandria on May 7, 1851, with a run to the north end of Union Street and the tunnel, linking the line to warehouses and wharves along the waterfront. Nearby, the Smith and Perkins foundry manufactured locomotives for the Orange and Alexandria and other railroads. The tunnel is typical of cut-and-cover construction, apparently cut through the bluff overlooking the Potomac River and covered so streets could continue above, with stone sides and a brick barrel vault likely built over wood falsework using a centering technique. After World War I, it was deepened to accommodate higher boxcars. At the onset of the Civil War, Union forces took over the Orange and Alexandria line along with many Alexandria railroads; this northerly section became part of the U.S. Military Railroads, while track south of the Rappahannock River remained in Confederate hands. Both sections played a major role in Union and Confederate strategy and were a decisive element in the Confederate victory at the Second Battle of Manassas, or Bull Run. The tunnel gave the Union Army access to the wharves for shipping military supplies on car ferries south of Aquia Creek, the terminus of the Richmond, Fredericksburg and Potomac Railroad. Shortly after the Civil War, the old line was incorporated into the Washington City, Virginia Midland and Great Southern Railway, controlled by the Baltimore and Ohio Railroad. The tunnel then figured in the rivalry between the Baltimore and Ohio and Pennsylvania Railroads for supremacy in north-south trade across the Potomac River. After the Pennsylvania Railroad gained congressional authorization for exclusive use of Long Bridge, Baltimore and Ohio maintained a competitive position by offering trans-Potomac service by carfloats linking Wilkes Street with Shepherd's Ferry on the Maryland shore until about 1906. Wilkes Street track remained in operation until 1975, when declining industrial activity along the waterfront no longer warranted rail service, and the tunnel survives as Alexandria's only intact nineteenth-century transportation site.
