The Dulles Corridor Metrorail Project, also known as the Silver Line, is a 23-mile (37-kilometer) extension of Washington, DC’s existing Metrorail system. The project is being implemented in two phases by the Metropolitan Washington Airports Authority for the Washington Metropolitan Area Transit Administration (WMATA).
The line begins at East Falls Church and runs to Dulles International Airport, terminating in Ashburn, Virginia. The 11.7-mile-long (19-kilometer) Phase 1 segment, extending to the Whiele Avenue Station, was opened for public service in July 2014.
As part of the Authority’s Program Management Team, Mott MacDonald provided design and construction management oversight for all underground elements for Phase 1 of the design-build project.
This included the twin Tysons Corner Tunnels, constructed using cut-and-cover and sequential excavation techniques, and the Central 7 Station Ventilation Building and West Falls Church Yard Tunnel, constructed using cut-and-cover.
In Phase II, Mott MacDonald provided design management for the preliminary design for the 1.5-mile (2.4-kilometer) segment through the Washington Dulles International Airport. This included twin running tunnels and an underground Airport Station. As a result of an extensive alternatives analysis, the Authority is implementing Phase II with an aboveground alignment through the airport.
When completed, the Silver Line will have 11 new stations, including a Dulles Airport Station. The Silver Line will link Washington, DC with the airport and with the edge cities of Tysons Corner, Reston, Herndon, and Ashburn, Virginia.