BOSTON (WHDH) - A plan to improve service, safety, and reliability will cause major outages on some commuter rail and subway lines later this year, the Massachusetts Bay Transportation Authority announced Thursday.

Starting this summer, the MBTA says it plans to use an “aggressive approach” to push along its Infrastructure Acceleration Plan. The work will result in extended shutdowns in regular service.

“The 2020 Infrastructure Acceleration Plan will deliver these projects eight years faster than originally planned, and will result in track replacement, upgraded intersections, and station improvements,” the MBTA said in a news release.

The plan calls for “major” weekday outages on the Green Line’s E and C branches, in addition to weekend service disruptions on the Red, Orange, and Blue lines.

“Our administration is dedicated to building a better MBTA for our riders that is safer and more reliable, and the 2020 Infrastructure Acceleration Plan will help to achieve this goal faster,” Gov. Charlie Baker said. “The MBTA started these projects in 2019 and will continue a vigorous schedule of construction and repairs aimed to build a system that will move more people from point to point in less time.”

In addition to a full-month shutdown of the C and E branches, the MBTA says it has scheduled an 11-month suspension of regular Green Line service between North Station and Lechmere starting in May 2020. During the closure, the MBTA will accelerate efforts to strengthen the historic Lechmere Viaduct in coordination with the rebuilding of the elevated segment of track through East Cambridge and the realignment of the track to a new, relocated Lechmere Station.

The MBTA says it will offer complimentary shuttle buses to accommodate commuters during diversions of regularly scheduled rail service.

“The increased work, accelerated investments, and smarter planning for replacement service represents our new normal as we continue to build a better, safer, more reliable T,” MBTA General Manager Steve Poftak said.

The improvements over the course of the next 12 months are part of a five-year, $8 billion project.

In addition to other ongoing projects, key highlights for 2020 include:

On the Green Line:

C Branch: A 28-day closure in service for the entire street-level branch (Kenmore to Cleveland Circle) replaced with accessible shuttle buses from the beginning of July to the beginning of August to allow for the replacement of track and upgrading intersections.

E Branch: A 28-day closure in service for the entire street-level branch (Prudential to Heath Street) replaced with accessible shuttle buses as well as enhanced Route 39 bus service (which operates alongside the E branch on Huntington Avenue) during the month of August to replace track and upgrade intersections.

GLX/GLT: Green Line Extension and Green Line Transformation work is also taking place for both construction of the new Lechmere Station and work on the Lechmere Viaduct with accessible shuttle buses replacing service between Lechmere and North Stations from May 2020 through April 2021.

B Branch: Three weekend diversions in June from Boston College to Babcock Street to replace track and upgrade intersections.

D Branch: Evening and weekend diversions throughout the entirety of 2020 for track and signal improvements as well as work on the Fenway Portal Project.

Work among all branches will result in 10.8 miles of track replaced (24 percent of the Green Line) and fourteen intersections upgraded (26 percent of the Green Line) with work completed over two years (760 days) faster than previously planned.

On the Red Line:

Eleven weekend diversions in which shuttle buses replace trains between Alewife and Harvard began in January and continue through April to repair 32,000 feet of track (6 miles, including concrete track foundations) and tunnel leak mitigation work.

South Shore Garage work on the Braintree and Quincy Adams Garages is accelerating with the goal to fully offset impacted parking spaces during construction. Four hundred parking spots will be returned to full use fourteen months early.

This work will be completed over a year (490 days) sooner than previously scheduled.

On the Orange Line:

Seven diversions (with the project continuing through 2021) in which shuttle buses replace trains between Oak Grove and Sullivan from October to December to replace 18,400 feet of track (3.5 miles) and associated systems at Wellington yard, modernize three escalators and upgrade traction power substations (which are 40+ years old).

This work will be completed 180 days faster than previously planned.

On the Blue Line:

Extended early access and 19 weekend diversions between Bowdoin and Airport from May through October to replace up to 2,500 feet of track (0.5 mile), repair isolated cracked rail within tunnel areas, open tunnel niches to build new truck pads, perform tunnel leak repairs, remove inactive cables and ducts, and perform tunnel weather-proofing work.

This work will be completed over two years (760 days) faster than previously scheduled.

On the commuter rail:

Franklin Line: Extended early access and weekend diversions in which shuttle buses replace trains between Forge Park and South Station as well as diversions to local transit services at the Franklin Street crossover.

The acquisition of eighty bi-level coaches is being accelerated to improve reliability and capacity, replacing the oldest passenger coaches in the fleet.

This work will be completed over 180 days faster than previously planned.

On the Silver Line and systemwide:

Silver Line: Extended early access and eight weekend diversions in which Silver Line buses will run at the street-level to waterproof compartments at Courthouse Station and East tunnels to reduce future leaking and enhance station conditions.

Repairs are also being made to parking lots systemwide at multiple parking facilities.

This work will be completed over an entire year (480 days) faster than previously planned.

To keep commuters informed about the upcoming work, the MBTA has created a specially designated website and interactive map.

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