Transportation Secretary Ray LaHood plans to hold a meeting Wednesday with the shareholders involved in building Metro’s new Silver Line because there is growing concern that starting construction on the second part of the rail line is delayed.

The move comes as the Metropolitan Washington Airports Authority said Wednesday it would not put out requests for quotations on the project until Loudoun County supervisors vote on whether to help pay for the project. The supervisors have until July 4.

Recently, Virginia lawmakers have been concerned about putting money into the project because they are worried about offering an incentive to prospective contractors if there is a pro-union work agreement. And Loudoun County supervisors have wanted more details about the project before they agree to contribute money.

 Last fall, LaHood helped negotiate a deal among the stakeholders in the project -- MWAA, Metro, Loudoun and Fairfax counties, and Virginia --  on how to finance the nearly $3 billion rail line.

The first phase of the project, which runs through Tysons Corner to Wiehle Avenue, is under construction and expected to be completed in August of 2013.

Construction on the second phase, which runs to Dulles International Airport and Loudoun County, was expected to start early next year.

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