The US state of Virginia has secured $116m in funding from the Department of Transportation (DOT) for the first phase of the $2.8bn Dulles Metrorail project in Fairfax county.

The latest funding is part of $900m in federal funding that has already been committed to the project.

US Senator Jim Webb said the investment brings Northern Virginia one step closer to a crucial Metrorail extension that will relieve congestion, improve quality of life and foster sustained economic growth in the region. "As Northern Virginia continues to be one of the fastest growing regions in the country, the Dulles Metrorail project will help meet the area’s overwhelming need for alternative modes of transportation," Webb said.

The first phase of the Dulles Metrorail project has been underway since March 2009, with 30% of its construction already completed by July 2011, and will be entirely completed by 2013.

The first phase includes construction of a 11.7-mile heavy rail line from West Falls Church station through Tysons Corner to Wiehle Avenue in Reston, Virginia. This project will consist of five new stations, improvements to an existing rail yard, 64 new railcars, and 2,300 parking spaces at the Wiehle Avenue station.

Upon its completion in 2017, the second phase extends the line another 11.6 miles from Wiehle Avenue in Fairfax county to Washington Dulles International Airport and to Route 772 in Loudoun county. The entire project will include 11 stations and entails a proposed 23.1-mile extension of Metrorail to Dulles International Airport.

Last month, Fairfax County revealed that it will raise third-party funds to pay all or part of the cost of the Route 28 Metro station and two parking garages.

The station and two garages are estimated to cost about $188m. Fairfax county will contribute 16.1% of the total cost for these facilities, as originally agreed, with its share estimated to be between $893m and $923m. Nearly 4.8% will be met by Loudoun County, 4.1% by the Metropolitan Washington Airports Authority and 75% by Dulles Toll Road revenues.

The county also plans to apply for a federal loan of up to $315m to meet the costs of the project, while Virginia has contributed $150m to the project in a bid to keep tolls low on the Dulles Toll Road.