PITTSFIELD — The concept of daily passenger rail service between Pittsfield and Boston survives, after local elected officials succeeded in banishing use of buses for the last leg.

But, as a long state Department of Transportation study wraps up, those leaders face a new fight: overcoming math that assigns a relatively low value to the statewide project.

And as a result, gives it scant chance of securing essential federal backing.

Members of an advisory group took issue with calculations by the DOT and its consultant about potential ridership during a briefing Wednesday.

State Rep. William "Smitty" Pignatelli, D-Lenox, believes benefit-cost data in the DOT study fails to capture the worth of what he calls a once-in-a-century investment. Once the study is finished at the end of November, elected leaders must enlist the help of U.S. Rep. Richard E. Neal, D-Springfield, and press for passenger rail to advance, he said in an interview Wednesday.

"We've heard it loud and clear from the state that this project will not move ahead without a large chunk of federal dollars," Pignatelli said. "Without Congressman Neal, we're in trouble, because these numbers just don't add up."

In a briefing Wednesday, the DOT's manager warned that a ratio based on costs and benefits of the proposed rail service — starting two decades from now, at best —falls far below the number reached by projects that typically win federal funding.

The three final options range in cost from $2.4 billion to $4.6 billion. The study estimates daily boardings of 922 to 1,554 people. Depending on the option chosen, travel between Pittsfield and Boston would take from 2 hours, 49 minutes to 3 hours, 9 minutes.

The capital cost estimate for just the Pittsfield to Springfield track work is $383 million.

When the project kicked off nearly two years ago, the DOT chief, Stephanie Pollack, warned that its cost could doom it.

Ethan Britland, the DOT's project manager, told members of the project's advisory committee by videoconference that the benefit-cost analysis came up with a ratio that falls as much as 10 times short of the figure needed, under current federal rules, to render a project "more competitive for discretionary grants."

That ratio is 1.0. The rail project study, using models of rail travel elsewhere in the New England, produced benefit-cost analysis ratios ranging from 0.08 to 0.12.

"With BCAs this low, it would be challenging," Britland said.

Pittsfield Mayor Linda Tyer questioned why service between her city and Springfield would take 1 hour and 12 minutes, with trains averaging 44 mph speed along a winding and steep corridor. She noted that the time is close to what it takes to travel by car and provides little incentive for people to change their habits.

Tyer said that if the project were to get the green light, the western section should be built first "because we currently don't have any passenger rail service," she said.

Only Amtrak now stops in Pittsfield, but at a cost to passengers much higher than commuter rail. Tyer argued that service has the potential to change decisions people make about where they live, enabling commuters "to live here and work there."

For that reason, she suggested that the ridership estimates, which affect the benefit-cost calculation, are off.

Tyer also questioned why the DOT analysis of ridership on comparable rail service did not include possible gains by drawing travelers who now use roads like the Mass Pike.

Britland said the DOT's analysis was already complete and suggested the question be included in a future study.

Who might do that study, and when, remains unclear.

Thomas Matuszko, executive director of the Berkshire Regional Planning Commission, asked Britland to explain what the DOT plans to do next to advance the project. Britland demurred, saying, "We're in listening mode now. We are looking for what you feel would be the next steps."

That stance came as no surprise to Pignatelli, he said later. "I don't believe the state is truly committed."

Rather than attempt to operate on lines owned by the private rail freight company CSX, as is now the plan, Pignatelli suggested the state acquire the lines and be the landlord.

"I say make CSX the tenant and see if they can abide by our rules, and not vice versa," he said.

State Sen. Adam Hinds, D-Pittsfield, noted that a bond bill now before a conference committee contains $250 million in funding that could be used to acquire the CSX track, or to create an entity able to run passenger rail service.

Travis Pollack of the Metropolitan Area Planning Council said it may be helpful to design a pilot program providing initial service. But others question the wisdom of that, fearing that partial service, particularly if expensive, would not be a fair test of what could be achieved, over generations, with passenger rail.

"It's going to send a very bad picture going forward," Pignatelli said of a limited pilot effort. "A pilot will validate that the ridership's not there."

Not yet, he means. But in his view, that public interest would be there by 2040, a start date in the state's modeling.

"I'm not worried about the ridership," said Pignatelli, who has been outspoken about the study's potential and missteps.

Members of the public will be able to join a videoconference planned for Oct. 22 on the report, with details to come later this week. A draft will be posted to the project's website Oct. 16, officials said. The final report is due Nov. 30.

"I think we can make this thing happen," Pignatelli said. "Western Mass., we've got to stick together, otherwise we will never see it in the Berkshires. This is for the next 100 years. This is a missed opportunity if we don't band together and force this."

Larry Parnass can be reached at lparnass@berkshireeagle.com, at @larryparnass on Twitter and 413-588-8341.