Metro mayors want RTD to chip away at the FasTracks budget deficit before they consider how much of a tax increase they might have to ask from voters to build the whole program.

The mayors said if they end up advocating a public vote for a second FasTracks sales tax hike, they need to tell the public every other step was taken first.

"I'm hesitant to say let's go tax the people until we know what kind of oversight we have" over RTD's costs, Broomfield Mayor Pat Quinn said.

"We have to be sure RTD is doing everything possible to be good stewards of public money," added Lone Tree Mayor Jim Gunning.

The comments came as mayors went through various ways to find new revenue or shave costs. There's a $2.1 billion deficit in FasTracks.

"It's like somebody's trying to lead me down the path to a large tax increase and that concerns me," Thornton Mayor Erik Hansen said. "I'm concerned about whether it would pass, and I don't believe that a large tax increase is good in this current economy anyway."

Among the items on the table:

* Seek a voter transfer to FasTracks of the metro stadium sales tax, 0.1 cents, that built Coors Field and Invesco Field, when it expires in 2012.

* Accelerate construction, which could save $100 million.

* Relocate the recommended site for a maintenance yard for new train cars. The current site requires RTD to move a bus facility.

"We have to put some responsibility on RTD to find some savings," Bill Vidal, Denver's public works manager, told RTD staffers. "Everything we come up with, you shoot it down."

69 PROPERTIES MUST BE ACQUIRED BY RTD

RTD says it needs to acquire 69 properties, six of them with homes, along the FasTracks East Corridor to Denver International Airport Â? a $1.7 billion project that's the second new line coming out of the chute.

The details are in a draft environmental impact statement from RTD that also says the airport train will cut off three freight railroad sidings serving the Stapleton warehouse district south of Smith Road between Dahlia and Kearney streets. RTD will have to compensate those businesses.

The 23-mile line would connect Denver Union Station with the airport, with trains running every 15 minutes. Its projected opening is 2015.

Public comment will be accepted through March 16. Public hearings on the plan will be from 5:30 to 8:30 p.m. on March 4 at North Middle School, 12095 Montview Blvd., and March 5 at Bruce Randolph Middle School, 3955 Steele St.