WASHINGTON -- Virginia Gov. Timothy M. Kaine said Tuesday he has been talking directly with Transportation Secretary Mary Peters to address doubts raised by federal officials that could kill the long-planned rail extension to Dulles International Airport.

Federal Transit Administrator James S. Simpson informed Virginia officials on Thursday that the project was unlikely to qualify for $900 million in federal funding, without which the entire $5 billion package would collapse. The news took the state by surprise. Officials had believed the project was on track for approval.

Speaking on WTOP radio's "Ask the Governor" program, Kaine held out hope that the federal funding could be salvaged.

"Secretary Peters has said, 'We want to get to the bottom of this and wrestle with it,"' Kaine said.

Peters, who is Simpson's boss, has the final say, the governor noted. He said he had spoken to her briefly at President George W. Bush's State of the Union speech and they "had a good exchange."

Virginia officials plan to write to Peters by Friday, Kaine said, and in answering Simpson's concerns will probably "invite some further dialogue."

Issues authorities may discuss include why Congress received a report that gave the project a medium rating at the same time the FTA told Virginia officials the project was rated medium-low, making it ineligible for federal money, News4's Julie Carey reported.

Sarah Echols, a Department of Transportation spokeswoman, said the secretary's office and the Federal Transit Administration "continue to communicate with the project sponsors and all parties involved as they seek to address the serious risks that face this project."

Kaine reiterated that until last week's meeting, state officials were under the impression that the project was on its way to approval. Over the summer, the FTA said the project was too expensive, so the state proposed cuts to reduce the price tag for the first phase of the extension from $2.8 billion to $2.5 billion.

Kaine said the FTA accepted those cuts, though Simpson questioned their validity last week.

With the funding in doubt, some have raised the possibility that the project could attract private investors. But Kaine said that such a scenario would still require the money to be made up somewhere. The easiest way to do that would be further toll increases on the Dulles Toll Road, which have already been raised to provide some of the funds for the project.

"My worry would be that the toll requirements would be exorbitant," he said.

Kaine said the project should have some federal contribution, given the significance of the airport, which is relied on by members of Congress and their staffs, as well as international diplomats.

"Let's get back to the common sense here, which is this is a huge federal asset, a huge asset in this region," he said. "There is really not an effective future for growth of Dulles, for growth of this region without rail."

That view was echoed in a full-page ad taken out in Tuesday's Washington Post by several business groups. The ad included an open letter to Bush from the Dulles Corridor Rail Association, the Washington Airports Task Force and the Greater Washington Board of Trade, urging him to help move the project forward. It also directed supporters to an online petition at DullesMetrorailNow.org.

"We just want to make sure that our elected officials know, which I think they do at this point, and the federal government know that this is an important project, and the citizens and the business community, by and large, is completely supportive of this project, both from a local level and from a national level," said Jonathan Cherner, who owns an auto dealership along Route 7 in Tyson's Corner.