For years, experts had said that the $7.3 billion estimate made in 2015 was probably too low . On Monday, officials from the Massachusetts Bay Transportation Authority stressed that the earlier figures and the more recent number are not directly comparable, because they used different methodologies to reach their conclusions.

The new figure, unveiled at Monday’s meeting of the MBTA, accounts for nearly all things transit: trains and buses, tracks and power systems, culverts and tunnels and bridges, and more. But some elements of the system have not yet been closely analyzed, and their costs are based on best-guess placeholders — meaning the figure could still jump once the analysis is complete.

The cost to fix or replace the MBTA’s aging equipment and upgrade to new, modern infrastructure is now valued at a cool $10 billion, a dramatic jump from the already eye-popping estimate cited just four years ago.

“You can’t really draw a line from one to the other and say, well, this asset got more expensive or less,” said general manager Steve Poftak. “They’re two fundamentally different things.”


But ultimately, he said, the cost is closer to $10 billion than $7 billion. “The current version is a much more accurate, precise, and a real assessment of the actual cost to the MBTA,” Poftak said.

The reason for the difference is that the latest review took a more in-depth look at various pieces of infrastructure, based on new federal standards. Also, it included costs that the prior number didn’t — such as the price of designing projects, upgrading infrastructure to include modern technology, and paying for bus diversions during major track work.

The 2015 estimate, by contrast, assumed that each piece of equipment would be replaced by a similar piece of equipment without accounting for new technology or design changes that ensure projects follow local and federal codes, or other related costs.


While that new level of analysis makes for a bigger price tag, the T said that some of its transit infrastructure has improved in recent years. For example, a few years ago nearly three-quarters of the T’s vehicles were considered too old under federal standards. That number has since been reduced to 32 percent as hundreds of new buses have entered the system.

“Absent the considerable capital investment over the last few years . . . this capital need assessment would be significantly higher,” said Samantha Silverberg, the T’s director of capital planning.

Even at the high cost, Poftak said, the MBTA will be able to tackle the many repairs.

“It makes the challenges more apparent. I don’t think it makes it more daunting,” Poftak said. “We know we are headed in the right direction, and we have to plan to address the entire capital need. This just gives us more insight . . . about where to prioritize the spending.”

Poftak added that some of the high costs will fall off in relatively short time, because projects that are underway but not yet complete are still counted as part of the backlog at their total cost.

Steve Poftak in 2017. Pat Greenhouse/Globe Staff/File/Globe Staff

So when new cars for the Red and Orange lines enter service in coming years, for example, the figure will go down by hundreds of millions of dollars.

But the price tag reflects only the amount of investment the T must make to improve existing infrastructure, meaning there will still be other costs associated with other goals, such as adding capacity with additional vehicles, expanding the transit network, or adding safety systems.


The $10 billion figure alone is an 11-digit behemoth that officials must act urgently to attack, said James Rooney, president of the Greater Boston Chamber of Commerce, who has been leading a charge by the business community to speed up investment in the troubled transit system.

Rooney, who sent a letter to the MBTA board encouraging more investment, believes the current spending plan is not good enough.

“It’s going to cost money. It's going to cost real money,” he said. “We have to come to grips with that.”

The existing plan, he argued, “is not the kind of activity and response we need to reflect the urgency of the situation.”

At the same time, Rooney noted that the T has had a number of recent hiccups with big pending projects — the slow introduction of new Orange Line trains to service, problems with federally required safety equipment on the commuter rail system, and an indefinite delay in replacing the fare-collection system — and questioned whether the T is even capable of handling such a huge backlog.

He wondered whether the state should establish a new transit construction agency, taking these types of projects out of the MBTA’s hands.

Poftak’s plan, which the T’s board has endorsed, is to hire new project managers and other employees at the agency who could more effectively oversee a big spike in spending over the next few years.


The goal is to boost spending on repairs and modernization to $1.5 billion a year by 2023, allowing the agency to beat back its backlog of repairs by 2032.

Governor Charlie Baker has declined to say whether the T will need new funding to reach that level of spending in the future, though on Monday he said he was planning to file a new transportation borrowing bill. Some lawmakers and advocates, however, have said they would like to seek new funding sources, such as raising the gas tax or fees on ride-hail services.

Poftak on Monday said that the T has enough money on hand to meet its spending goals through the 2024 fiscal year and that the agency must still prove it can effectively spend $1.5 billion a year.

Adam Vaccaro can be reached at adam.vaccaro@globe.com.