WASHINGTON -- The Depart-ment of Energy has doubled its estimate of what it would cost to build a railroad across rural Nevada to transfer nuclear waste to the proposed Yucca Mountain repository, officials confirmed on Tuesday.

The projected price tag of a 319-mile line now stands at $2 billion. A DOE spokesman said the updated estimate also includes construction of rail yards and other maintenance features along the route.

The DOE in a 2002 environmental impact study estimated it could build a 300-mile railroad at a cost of $880 million in 2001 dollars. The figure was greeted with skepticism at the time by repository critics.

Robert Halstead, a Wisconsin-based consultant for the state of Nevada, said the new estimate is probably more realistic, and still may prove to be low for what he said was a challenging route that crosses several mountain ranges and high desert terrain.

"I've been saying at least a billion and a half dollars and up to 2 billion based on engineering analyses we did back in 1996, when we knew less about the problems of that route than we do now," Halstead said.

The revised costs also underscores the growing costs facing the repository project, which has been repeatedly delayed since its original opening date of 1998. The most recent official cost estimate for the overall repository was calculated in 2001 at $58.5 billion, a DOE spokesman said.

An official familiar with the project said DOE managers "had a big gulp about six months ago" when they projected new costs for the Nevada railroad. The department is preparing an environmental impact study of its preferred rail corridor that has included public meetings in rural Nevada and meetings with ranchers along the route.

The DOE has proposed to build a rail line from the outskirts of Caliente west and north to Warm Springs, then curling around the northwest boundary of the Nevada Test and Training Range managed by the Air Force. The railroad would follow the western border of the test range south to the Yucca site.

Companies that expect to bid for shipping contracts plan to seek more details of the cost figures, said David Blee, a spokesman for the U.S. Transport Council, their trade group.

"Clearly we are interested in knowing the cost basis," Blee said. "We are always concerned about cost escalation in the program, particularly in the vital transportation component."

The new cost projection also gave fresh ammunition to Yucca Mountain critics, who contend that burying nuclear waste in Nevada is a boondoggle at any price.

"It would be cheaper to build a road paved with gold," Rep. Shelley Berkley, D-Nev., said of the railroad. "Yucca Mountain is already slated to be the most expensive public works project ever undertaken by the government, and just like this ridiculous railroad boondoggle, its price tag continues to spiral out of control."

The Nevada railroad will provide "another funding challenge with Congress," said Christopher Kouts, a Yucca project manager.

Halstead said growing costs may cause the Energy Department to think again whether it wants to ship nuclear waste to Yucca Mountain by rail. The department also has considered shipping waste canisters by rail to Caliente, than transferring them to trucks for transport to the repository.