When Joe Aiello, the chairman of the MBTA’s Fiscal and Management Control Board (FMCB), was growing up in East Boston, riding the T was how he got around.

"It really did transform my life,” said Aiello. “In many ways it was the internet of my generation. You sort of got around and saw things outside of your neighborhood.”

Little did Aiello realize that someday he would be leading an effort to completely rebuild the transportation system, including replacing some of the same Orange and Red Line cars he rode as a teenager. Soon after Gov. Charlie Baker took office in 2015 and not long after “Snowmageddon” ground trains and buses to a halt, the governor created the five-member FMCB to oversee the management and finances of the MBTA and get the region’s transit system back on track.

Fast-forward four years, and Aiello is guiding the MBTA through major infrastructure projects after a number of derailments upended commutes and forced T riders to make alternative travel plans earlier this summer. The MBTA announced Monday that key portions of the Orange, Red and Green lines will be shut down on weekends in the fall in an effort to speed up desperately needed repairs.

Read More: MBTA Shutdowns: What's Open, What's Closed, What You Need To Know

That effort is being spearheaded by the FMCB. Aiello, who worked at the MBTA as assistant general manager of planning and budget and assistant director of construction for special projects and finance during the 1980s, said these short-term disruptions, which may go beyond the fall, will be worth the long-term results.

When the FMCB was created, almost every part of the T was in disrepair. The subway cars and trolleys were old — so old that replacement parts had to be manufactured in MBTA maintenance shops since they weren’t being made anymore. The 1,000 buses in the fleet were aging, running old routes and schedules, and polluting the air with diesel fumes. The commuter rail was plagued with old locomotives that frequently malfunctioned, creating delays.

Although Aiello admitted there is still a long way to go to fix the system, he said progress is being made. Investments have been made to replace the basic infrastructure, including some power and signal systems that are nearly 100 years old. Many of those investments are "in the pipeline" and not apparent yet. But Aiello said customers will begin seeing the results of those investments later this year, as the new Orange and Red Line cars come into service, and the entire 1,000 bus fleet is replaced by cleaner hybrid vehicles.

He is not on social media and doesn’t follow Twitter, but Aiello is aware of the criticism constantly leveled against the transit agency. The most common complaint: Why isn’t anything being done to fix the T?

"That's a question we get a lot," Aiello said. "Certainly, I understand the frustration of the rider on a day-to-day basis. They don't see what appears to be any dramatic changes in the level of service they're getting, so I have great sympathy with them and am equally impatient, as is all the board, with the pace of progress. Our goal is nothing short of having a globally premiere transit system. It’s going to take a long time to get there, but we're certainly making major investments moving in that direction.”

He points to a $566 million contract signed in 2014 for 152 Orange Line cars and 252 Red Line cars. In 2016, the state upped the order with another 120 new Red Line cars, with production set to begin in June 2022 at a cost of $277 million. The first new Orange Line cars now being tested will be phased into service starting Wednesday. In addition, six miles of new track for the Green Line D Branch is being installed, and the three-mile extension of the Green Line costing $2 billion is underway to Cambridge, Somerville and Medford.

Commuter rail improvements will take longer than the subway and bus lines, as a rail vision study is underway and due to be finished next year. (That review will examine electrification and improving frequency, scheduling and capacity of the trains.) Half of the 40 locomotives in the fleet have been rebuilt, with work continuing on the remaining 20 engines. Even with its limitations, Aiello said commuter rail on-time performance — which the MBTA defines as within five minutes of the schedule — is above 90 percent for first time. He said the crowding that many riders complain about is actually a good sign, showing that so many more passengers are taking the trains to and from work.

But all of these improvements are taking an excruciatingly long time to accomplish, and Aiello is well aware of the criticism.

He does praise the myriad of transit advocacy groups voicing their opinions.

"They don't just complain. They complain and suggest that we do things differently, and that we think differently,” he said.

And that, Aiello said, has resulted in many positive changes — which is how it should be.

Aiello once told WGBH News that even when the T is “fixed” — referring to the state's all-encompassing $10 billion plan to address the maintenance backlog, which isn’t scheduled to be completed until 2032 — it will be out of date because it's a system designed for Boston of the 1960s, not the city we live in today or into the future as growth continues. Aiello said that means we’ll need more and better mass transit, including expanded bus service and fixing the much-maligned commuter rail, for which Aiello sees dramatic changes ahead.

"It wouldn't surprise me that we're going to make a decision in the first part of 2020 that the current sleepy commuter rail system becomes a supercharged regional rail system, with more frequent service and some mix of electrified service," Aiello said. "We've got rather wealthy people moving into the city, moving into Somerville, Cambridge and other places. And folks of lesser means are being forced out. ... They still have to get into Boston to do their jobs, and commuter rail isn't priced right, I don't think.”

Aiello said a new automated fare collection system that’s still in the works will allow those fare inequities to be addressed.

The T's fiscal control board is set to go out of business next July, but even if its life is extended, Aiello hinted he may not be staying on.

“It's really been an honor to serve in this position, there's no doubt, and it's been a thrill despite the frustration sometimes," he said. "I think it's important, as you move forward, they need to hear a different voice."

But Aiello said even if Baker's Fiscal Management and Control Board ends as scheduled next summer, some kind of T oversight board will be needed.

“This job of moving the T to be able to serve the community the best it can ... never ends,” he said.