D.C. Mayor Vincent C. Gray now supports locating a new Metrorail station at Dulles International Airport above ground.

Gray revealed the switch Wednesday morning. He said his position changed after discussions with Virginia Gov. Robert F. McDonnell on Tuesday and having lunch with former Virginia congresssman Tom Davis last week.

Davis now serves on the board of the Metropolitan Washington Airports Authority, which is overseeing construction of the new rail extension to Loudoun County. McDonnell’s administration has endorsed an aboveground location for the Dulles station, and Davis has been an opponent of the underground site.

Critics have said the airports authority needs to reduce the ballooning costs of the second phase of the project, now estimated at $3.5 billion. The Federal Transit Administration has estimated that the aboveground location could shave $400 million from the project. It would also be located about 600 feet farther away from the main terminal than an underground stop, which the board endorsed in April.

“I don’t want to wind up with nothing,” Gray said during a news conference Wednesday. The mayor said he has communicated his change in position to D.C. members of the board of the Metropolitan Washington Airports Authority, but “They will have to cast their votes.”

The Metro line is being constructed in two phases, with the first part of the project underway and scheduled to open by 2013.

U.S. Transportation Secretary Ray LaHood has been mediating talks between local leaders and the authority in an attempt to reach a consensus on the project.

Last week federal transportation officials proposed to shrink the cost of the second phase, scheduled to open by 2016, by building an aboveground station at Dulles International Airport and transferring responsibility for parts of the project to local governments. Stakeholders were asked to take the proposal to their groups and to reconvene in mid-July.

Gray’s comment came as the airports authority board met behind closed doors Wednesday to discuss LaHood’s proposal.