By Keith Laing - 12/02/13 05:17 PM EST
The Washington, D.C. Metrorail subway system's extension toward Dulles International Airport has been delayed, officials building the line announced on Monday.
Construction on the new Metro line, which has been dubbed the Silver Line, was scheduled to be completed by the end of November.
However, the Metropolitan Washington Airports Authority (MWAA), which runs Dulles Airport and is building the new Metro line, said on Monday that it needed more time to test the new line before it transferred control over the railway over to Metro.
"This is why we test," Dulles Corridor Metrorail Project Executive Director Pat Nowakowski said in a statement. "Our guiding principle throughout this process has been ‘safety first’ and we remain committed to that principal. We will not do anything that might compromise safety or create unsafe conditions for the traveling public."
The Silver Line will be operated by the Washington Metropolitan Area Transit Authority (WMATA) after it is opened.
The transit line, which is one of the largest currently ongoing public transit projects in the U.S., is being built in part with $900 million from the Obama administration.
The Washington airport authority had predicted it would transfer control of the Silver Line over to Metro by the end of November, but the transit agency had not announced a firm start date for the railway.
The first phase of the Silver Line is scheduled to run from Prince George's County, Md. to Reston, Va., with stops throughout the capital city's downtown core.
The Silver Line's second phase, which is planned to include the stop at Dulles Airport, is not scheduled to open until 2018.