Spiraling cost estimates for the Ashmont Station renovation could force MBTA designers to scale back the list of amenities and further delay the start of construction.

Construction bids outpaced T construction cost estimates by a minimum of more than $10 million, with one bid exceeding forecasts by more than $21 million. The frail economy makes procurement of additional public funds difficult, several city and state government officials said.

Sticker shock has forced T officials to regroup and evaluate the feasibility of the project.

"We're analyzing the bids and trying to figure out the most cost-effective way to move forward with it," said Barbara Boylan, the T's design director, at a Monday night community meeting about the Mattapan Station renovation. She said the transit authority would form a plan within two weeks.

T spokesman Joseph Pesaturo said, in a voicemail, "The MBTA's design team is compiling a list of items to consider in an effort to lower the cost of the project." By mid-February, he said, "We will be able to provide some alternatives to the public in terms of getting the cost down.

T officials declined to speculate publicly about what amenities could be eliminated or to discuss a redrawn timetable.

With a total project cost, as of last fall, of $44 million, the Ashmont rehaul is the most ambitious of Dorchester's four Red Line station projects, but concerns about rising construction costs have led T officials to reexamine its scope and schedule, said several sources familiar with the project. Initially scheduled to proceed on a timetable parallel to the other three stations', Ashmont work was pushed back in early 2003 after neighborhood activists lobbied for more time to consider design adjustments. Under the revamped schedule, T and state officials said, construction was slated to start in the spring.

But contractors' bids, requested last fall, have been coming in at prices above the money allotted by the state. While the T opened bids at $33 million, the lowest bidder, the Barletta Heavy Division contractor who is overseeing work on other stations, came in at $43.8 million. J.F. White Contracting company bid $47.8 million, and Jay Cashman, Inc. registered a $54.5 million bid.

Steel costs that have risen to their highest in a quarter century, driven by a global surge in manufacturing and the weakened U.S. dollar, are pushing up the costs of development.

"It's not unusual to think that they'd be over-budget with those kinds of construction cost increases," said Chris Stanley, co-chair of the Ashmont community advisory committee (CAC) and an architect for a Cambridge firm not associated with the project. Stanley said many residents would agree to remove some aspects of the project it spent years negotiation with T designers.

"We've all been working on it too long to say, 'That's it. It's got to be the way we said it was going to be'," Stanley said Monday.

But co-chair Rosanne Foley called rumors of budget overruns "very disappointing," and said the notion of paring back the project's ambitions was disheartening.

"The station is just so nifty the way it is now, I hate to go back to the drawing board," she said. "It really seemed like it was going along really well."

Both state Sen. Jack Hart and City Councillor Maureen Feeney said they would ask T General Manager Michael Mulhern for a meeting before the authority's Feb. 10 board of directors meeting.

"I think the community should expect that the MBTA live up to the agreement," Feeney said.

Complicating the station work timeline is an adjacent project, a 30,000-square-foot development parcel owned by Trinity Financial, a Dorchester-based firm hoping to convert the space into a combination of first-floor retail and second-floor residential space. Delays or alterations in station work could jeopardize the project next door, Stanley said.

"If it comes to that, then we'll have a really expensive parking lot in front of Ashmont Station," Stanley said.

Trinity project manager Vince Droser said the firm's design plans have not changed, but acknowledged the planned springtime construction start could waver.

"That might slip now," Droser said, "but hopefully it'll only slip a few weeks or a month."

He said the project's funding flows mostly from public agencies like state and city departments, who are unlikely to back away from a project they have backed.

Current design plans for the station, built in 1927, call for a thorough modernization. Its main entrance and two headhouses would be improved, and a continuous roof structure would cover the entire portion of the track within the station.

During design vetting, Ashmont residents pushed the T to weigh urban design principles consistent with a third facet of the area's redevelopment, a redesign of Peabody Square.

Problems in securing funds for the station and disagreements over design details have slowed the station's renovation, but the residents who have continually pressured the T and Trinity have said they were willing to yield timetable demands in exchange for a more complete renovation.

Now, with both priorities threatened, and with the potential domino effect posing difficulties for the private development project, once-optimistic rail advocates are expressing doubt.

Foley, who said at a September press conference with several leading state politicians that she was "floating on air," was less sanguine Monday. She said, "I'm kind of slowly sinking back down to earth here."

The T has consistently missed benchmarks and deadlines, most recently defaulting on its Savin Hill Station schedule. After pushing the January 2005 deadline back last November to February or March, the T announced last week that the station likely will reopen in May.

Much of the political muscle behind the Ashmont rehaul atrophied last fall, when then-House Speaker Thomas M. Finneran, announced plans to leave Beacon Hill for a private sector post. Lawmakers had divvied up loosely the responsibility for the four stations, and Finneran's was Ashmont, where he frequently boarded the Red Line into the State House.

At the Ashmont Station press conference in September, the week before he revealed his intention to step down, Finneran hailed the cooperation that had injected the necessary funding, and wryly genuflected to Governor Mitt Romney as a sign of thanks. In November, he called the Ashmont project an important part of his legacy.