Metro’s new Silver Line is coming under scrutiny as an engineering study detailing the price is reviewed and as Loudoun County is expected to decide soon on whether it wants to help pay for bringing the second phase beyond Dulles Airport.

The second part of the project, which is expected to run from Dulles Airport to Loudoun County, is expected to cost roughly $3 billion. Previous estimates expected Loudoun to contribute $260 million to the construction of the second phase.

The first phase of the 23-miles of the new Dulles rail project is being built and is expected to open in late 2013. It could be as much as $150 million overbudget, according to project managers. The Metropolitan Washington Airports Authority (MWAA) is overseeing the construction of the Silver Line.

Construction on the second phase could start in January 2013 and the second part could be finished in mid-2018 for passengers to ride.

Over the last few weeks, Virginia politicians, local jurisdictions and overseers are watching the Silver Line project closely.

The preliminary engineering study for the second phase cost roughly $45 million and was done by Parsons Brinckerhoff and Aecom. They turned in the study Wednesday to MWAA.

Pat Nowakowski, chief construction manager on the Dulles rail project at MWAA, said he is still reviewing the engineering report and expects to release it in the next several weeks to “the partners involved.”

The big question many observers want to know is — how much will it cost?

“We’re not ready to put that out there yet,” Nowakowski said.

Loudoun County officials are waiting to see the engineering study because they have a 90-day period to review the project. County officials could decide during that time whether they are in — or out — on paying their share to help build the second part.

Since the November elections when there was turnover on the board of supervisors there, some have questioned whether they’ll stay in the project.

A project labor agreement on the second phase has drawn controversy.

MWAA reversed its decision to have such an agreement after Virginia politicians threatened to push the governor to withhold an expected $150 million in funding on the project.

“I’m very concerned about what MWAA has been trying to do on its [project labor agreement] and that may be the icing on the cake for me to reverse my support” of funding the second phase, said Scott K. York, chairman of the Loudoun Board of Supervisors.

A proposal seeking contractors on the second phase is expected to go out by the end of March. Eight companies are expected to bid and the list will then be narrowed to five. A winner will be picked by the end of the year, MWAA officials said.

There are other matters to work out on the Silver Line.

On Thursday night, the Northern Virginia Transportation Commission (NVTC) is expected to review a plan of how it and Loudoun will interact with Metro in overseeing and paying for maintaining the new Silver Line.

Previous estimations expected the county would be paying between $8 million and $15 million a year as its subsidy to Metro to run the line. County officials said they do not pay for running Metrobus in the area. York said the county already has long distance and local commuter buses that will help service Metro stations.

“Simply put we don’t feel we need those Metrobus services,” he said.

Loudoun officials are expected to discuss their participation in the Silver Line project Wednesday, according to York.

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