Traveling on an MBTA train will get more challenging this year, but officials promise passengers: it will all be worth it in the long run.

All five main MBTA lines and parts of the commuter rail will now see shutdowns in 2020 in an expanded push to complete maintenance work more quickly. Most of the effects will be additional overnight or weekend closures, but in an unprecedented move, large chunks of the Green Line's C and E branches will each be taken offline for a full month.

Gov. Charlie Baker, Transportation Secretary Stephanie Pollack and MBTA General Manager Steve Poftak said Thursday that the plan, which builds on a model launched last year, can complete track replacement and station improvements up to eight years faster than with traditional methods.

"The goal of all this work is to deliver a safer, modern, more reliable T faster," Baker said at a press conference in a Brookline MBTA maintenance facility, backdropped by a brand-new Green Line train.

Every line will experience newly announced service disruptions in addition to previously scheduled closures as part of the accelerated maintenance plan.

Shuttle buses will be provided for passengers during some diversions, while the T will increase the frequency of trains on nearby lines during other shutdowns. Poftak said MBTA officials are "actively discussing" setting aside dedicated road space for buses to improve efficiency.

The most dramatic changes are on the Green Line. The C branch between Kenmore and Cleveland Circle running through Brookline will be offline for 28 days in July, while the E branch from Prudential to Heath Street through Longwood Medical Center and Mission Hill will be offline for 28 days in August.

Other Green Line branches will also see disruptions. The B branch between Boston College and Babcock will not run on weekends in May and June, and the D branch will not have evening or weekend service until 2021.

On the Red Line, trains will not run on April weekends between Alewife and Harvard. The Blue Line will be offline between Bowdoin and Airport on weekends from May through November.

A stretch of the Orange Line from Sullivan Square to Tufts will continue weekend closures into mid-February, and Oak Grove to Sullivan Square will be offline on weekends from October through December.

Silver Line service at Courthouse Station will be street-level only on weekends from August through December.

The T already planned to shutter weekend train service for several commuter rail lines, and as part of the expanded maintenance plan, the Franklin Line from South Station to Forge Park will be replaced by buses on weekends through March.

Officials acknowledged that the plan will create headaches for commuters, but they said the tradeoff will result in a more reliable public transit system. Construction of new Green Line track in 2020, Pollack said, will allow the T to eliminate speed restrictions and improve travel time by four minutes.

"Right now, the most disruptive thing that happens on the T is the unplanned shutdown, the train that breaks in service, the mechanical failure that shuts down a train," Pollack said. "The reason that we are asking our customers to tolerate these planned disruptions to their commute is to reduce and, hopefully some point, nearly eliminate the unplanned disruptions that really have been the biggest complaint we hear from our customers."

At Baker's suggestion, the T launched an accelerated maintenance plan last year after a derailment and months of delays on the Red Line prompted scrutiny of the system's aging infrastructure and frequent challenges. An outside panel later concluded that the T does not sufficiently prioritize safety culture.

Baker proposed a one-time, $50 million allocation to fund additional work, but the Legislature ultimately approved only $32 million of that amount as the House prepares to debate raising long-term transportation revenues. The governor is seeking the remaining $18 million in a separate bill.

The MBTA added 10 weekend shutdowns in the second half of 2019, but plans for 2020 are far more sweeping with about five times the amount of work planned, Poftak said. Crews will replace 29 miles of track, including almost a quarter of the entire Green Line, over the course of the projects.

"We listened to our customers," Poftak said. "Last year we heard them loud and clear: fixing the MBTA at our previous pace was not good enough. We needed to build a better T, and we needed to do it faster."

Poftak told reporters the MBTA already has the staffing it will need to accomplish the accelerated repair plan and, particularly if the Legislature approves the remaining $18 million sought by Baker, the money to pay for it.

"We have been actively hiring," he said. "The MBTA has hired almost 600 people in this fiscal year. We will continue to do that. In particular, we have added almost 100 positions in the critical departments in engineering and maintenance that will serve as support for this."