COMING UNDER FIRE for aging, crumbling infrastructure at the MBTA, Gov. Charlie Baker on Tuesday trumpeted his administration’s long-term investments in public transit and the promise of better service once new trains and tracks come online over the next several years.

Speaking at the unveiling of a mockup of a new Red Line car on City Hall Plaza, Baker said fiscal 2018 was the first time in a decade that the MBTA spent all of the money that it had allocated for so-called state-of-good-repair projects.

“Over the course of the next five years, the MBTA plans to spend $8 billion on its core system and the two expansions associated with the Green Line extension and South Coast Rail,” Baker said. “That will be $5 billion more than the MBTA spent in the five years prior to 2016. It’s a massive investment. It’s way overdue, and it’s a big part of how we deal with the deferred maintenance issues that have plagued the system.”

The T in the past has had difficulty spending the money it allocates for capital investments in the transit system because it lacked the staff needed to procure the contracts and oversee them to completion.

Even in fiscal 2018 there appears to have been some slippage on capital spending plans. A presentation to the T’s Fiscal and Management Control Board last November indicated the T planned to make $942 million in capital investments in fiscal 2018, with $795 million slated for state-of-good-repair projects – spending to maintain the existing system. According to a presentation in July (see general manager’s remarks), the numbers ended up being $867 million in overall capital spending and $717 million on state-of-good-repair projects.

The T plans to ramp up those numbers dramatically over the next five years, as spending accelerates for the purchase of all new Red and Orange Line cars, the Green Line extension into Medford and Somerville, and the installation of a new automated fare collection system. Investing $8.1 billion over the next five years would mean the T would spend an average of $1.6 billion a year.

Baker says those investments, as well as nitty gritty investments in tracks and signals, will eventually pay big dividends for riders in terms of more reliable and faster service.  Jeffrey Gonneville, the T’s chief operating officer, told the Fiscal and Management Control Board on Monday that the goal is to have Red Line and Orange Line trains arrive at stations at intervals of 3 minutes and 4.5 minutes, respectively. Currently, the intervals are 5 minutes and 6 minutes “on a good day,” Gonneville said. He said the reliability of the Red and Orange Lines ranges between 89 and 92 percent currently, but should rise to 95 to 96 percent on average with the new equipment.

Asked about the Alewife garage on Tuesday, Baker defended the T, saying a report in November identified serious safety issues at the garage and the transit agency responded by hiring a contractor to do $5.7 million of work on the facility starting in September. T officials have come under fire for not alerting the public or members of the Fiscal and Management Control Board to problems at the garage, leading some to speculate that the problems at the facility never reached top management until a piece of ceiling fell on a car last week.

Jay Gonzalez, who is seeking the Democratic nomination for governor, said the garage issue and Tuesday’s press conference illustrate a fundamental difference between him and Baker. “He defines success by budget numbers,” said Gonzalez, who, like Baker, once served as secretary of administration and finance. Gonzalez said he would define success by how well the T works for its riders. “By that measure, Charlie Baker is failing miserably,” he said.