DC Metro Silver Line extension 87 percent complete

By Keith Laing - 01/17/13 12:56 PM ET

The extension of Washington, D.C.'s Metrorail subway system that will eventually reach Dulles International Airport is 87 percent complete, the agency that is responsible for the railway’s construction said Thursday.

The Metropolitan Washington Airports Authority (MWAA) said it has moved from “heavy construction” to testing and electrical work on the first half of the new rail line, which will run 11.5 miles in the direction of the Dulles Airport when it is completed.

The MWAA is constructing the Silver Line for the Washington Metropolitan Area Transit Authority (WMATA), which is scheduled to begin testing of its own on the railway in August 2013. The WMATA has forecast a December opening for the Silver Line.

Transportation Secretary Ray LaHood has hailed the project as a model for other transit systems across the country, referring frequently to WMATA as “America’s subway” because it carries visitors to the nation’s capital.

The Silver Line extension is one of the largest heavy, or fixed, railways currently under construction. Many cities have trended toward developing light rail lines because of reduced construction costs.

The Obama administration has provided $900 million to the construction of the first phase of the Silver Line, which will run through northern Virginia’s Tysons Corner.

Construction on the second phase of the Silver Line, which will include a stop at Dulles Airport, is expected to begin next year.

Dulles Corridor Metrorail Project Executive Director Pat Nowakowski said the shift to testing on the first phase of the project “is a very visible sign of the project’s shift from intense heavy civil construction to systems and testing that are necessary to ensure the safe and reliable operations of the rail line.”

Read the MWAA's full Silver line update here.