IT HASN’T RECEIVED a lot of attention, but the MBTA has an extra $1.2 billion in untapped capital funds at its disposal.

The agency’s five-year capital spending plan has $9.4 billion in funding sources but only $8.2 billion in planned spending. T General Manager Steve Poftak said in May that he would like to spend more over the next five years, but he doesn’t think the agency currently has the organizational capacity to do so.

“Nothing would make me happier than to come back to the board in a year or two to say we need additional money,” Poftak said.

Others say the extra money should be put to use faster. They say the T needs to increase its organizational capacity, principally by hiring more people to oversee capital projects, while simultaneously increasing spending. “I would argue we need to walk and chew gum at the same time,” said James Rooney, the president and CEO of the Greater Boston Chamber of Commerce.

Rooney said the T is putting off a number initiatives to later years, including money for new vehicles for the Mattapan trolley line and the construction of the proposed West Station at Allston Landing.

“There’s a long list of things that are not programmed into the spending plan,” Rooney said. “It’s a long list.”

James Aloisi, a member of the TransitMatters board and a former secretary of transportation, said he would favor spending the extra money on a construction project connecting the Red and Blue Lines, but he noted the cost of that initiative would eat up only a portion of the funds. “There’s so many needs. There’s no end to the possibilities,” he said.

Even T insiders have called for using some of the funds. Joseph Aiello, the chair of the Fiscal and Management Control Board, in late June urged T officials to think more ambitiously about improving bus service. He suggested using $50 million of the $1.2 billion in surplus funds to help municipalities cover 90 percent of the cost of bus rapid transit service in their communities. Bus rapid transit would include dedicated bus lanes and other initiatives to speed up service and make it more attractive to riders.

T officials have been cautious in committing to additional capital spending beyond the $8.2 billion slated for disbursement between fiscal 2020, which began July 1, and fiscal 2024. Shortly after a Red Line train derailed at the JFK/UMass station on June 11, members of the T’s Fiscal and Management Control Board asked top MBTA officials if they needed more money. Transportation Secretary Stephanie Pollack referred to the extra $1.2 billion, and said the funding could easily be tapped.

But Poftak and Deputy General Manager Jeffrey Gonneville both said they would have trouble spending the $8.2 billion. Indeed, the T has never reached its annual capital spending target over the last several years, in part because the targeted spending level has continuously ratcheted upward. That’s why Poftak in May scaled back the existing $8.2 spending plan, calling it “infeasible to execute” in a presentation to the Fiscal and Management Control Board. By deferring some spending to future years and incorporating construction of South Coast Rail (and its $1 billion in dedicated state spending) into the plan, the five-year spending target remained at just over $8 billion.

Rooney, in a letter to the control board in May, said he was disappointed in Poftak’s decision to put off some planned capital spending. He described the situation as “essentially waving the white flag and declaring a capacity emergency.”

He welcomed the T’s push to expand its own capital delivery staff, but said other measures could also be taken, including the hiring of private sector management and engineering firms or creating outside the T a “professional capital infrastructure projects organization similar to the school building authority” to oversee capital projects.