Green Line (MBTA)

Green Line

Company type	Public transit
Industry	Public transportation
Founded	1897
Area served	Boston metropolitan region
Products	Light rail transit service
Owner	Massachusetts Bay Transportation Authority (MBTA)
Parent	Massachusetts Bay Transportation Authority (MBTA)

Green Line

The Green Line is a light rail network managed by the Massachusetts Bay Transportation Authority (MBTA) serving the Boston metropolitan region. It holds the distinction of being the MBTA's most historic subway route, with sections of its tunnels dating back to 1897, making it the oldest subway system in North America. The line operates underground through Boston's downtown area and extends above ground along six radial branches that travel through inner suburbs via boulevards and grade-separated pathways. In 2023, its average weekday ridership reached 101,000, placing it among the busiest light rail systems in the United States. The designation of green as its color was introduced in 1967 during a comprehensive system rebranding, inspired by several branches passing through Boston’s Emerald Necklace park network.

Originating from an extensive streetcar system launched in 1856 with the Cambridge Horse Railroad, the four branches eventually consolidated under the Boston Elevated Railway. All routes merge downtown via the Tremont Street subway—the oldest subway tunnel in North America—opened on September 1, 1897, to ease streetcar traffic congestion. This tunnel underwent five expansions over fifty years. The streetcar network reached its peak around 1930 before gradually being replaced by trackless trolleys and buses, with service cutbacks continuing until 1985. The D branch debuted in 1959 after converting a former commuter rail corridor. More recently, the Green Line Extension project extended two branches into Somerville and Medford, completed in 2022.

Route description

At its heart lies the central subway, a tunnel system running beneath downtown Boston. The Tremont Street subway travels in a north–south direction with stops at , , , , and , linking to other MBTA subway lines. Running east–west through Back Bay, the Boylston Street subway includes stations at , , , and ; it intersects with the Tremont Street subway at Boylston. Branching southwest from the Boylston Street subway near Copley, the Huntington Avenue subway serves stations at and . Additionally, a now-unused branch extends southward from Boylston to the former Pleasant Street incline.

The Green Line features four surface branches heading westward, each identified by a letter:

• The B branch departs west from Kenmore station, surfacing onto Commonwealth Avenue at . It spans through areas including Boston University, Allston, and Brighton before reaching Boston College station.
• The C branch heads southwest from Kenmore, emerging onto Beacon Street at . It serves communities such as Brookline, terminating at Cleveland Circle station.
• The D branch separates from the C branch tunnel near Kenmore and surfaces at Fenway station. It travels along a grade-separated former commuter rail line known as the Highland branch through Brookline and Newton, ending at Riverside station.
• The E branch proceeds southwest via the Huntington Avenue subway from Copley station, surfacing near Northeastern University station. It continues for along Huntington and South Huntington Avenues to ; its outermost section operates mixed with regular traffic instead of running in a dedicated median. Until 1985, this branch extended further south to .

While B and C branches terminate at Government Center station, D and E continue northward beyond downtown. Beyond North Station, the line rises onto the elevated Lechmere Viaduct, crossing over the Charles River with a stop at . The elevated Lechmere station on the Green Line Extension viaduct connects to a flying junction branching into two lines:

• The Union Square Branch runs westward to Union Square station along the former right-of-way of the Fitchburg Line, operated as part of the D branch.
• The Medford Branch extends northwest to Medford/Tufts station following the former right-of-way of the Lowell Line, operated as part of the E branch.

Former Lines

The Green Line A branch was the furthest north, extending from the Blandford Street portal—still utilized by the B branch—westward to Watertown Square, primarily operating on street-level tracks. In 1969, this streetcar service was replaced by MBTA Bus 57. The A branch separated from Commonwealth Avenue just west of Boston University and crossed the Charles River to reach Watertown Square until its closure in 1969. Although the route-letter system was introduced two years prior to its discontinuation, the "A" label was never displayed on streetcars traveling to Watertown but did appear on Boeing-Vertol LRVs during the mid-1970s when a reopening was contemplated. The tracks remained intact for non-revenue purposes, mainly maintenance access, until 1994.

Two final routes operated through the Pleasant Street portal: Bus 9 to City Point ended service in 1953, while Bus 43 to Egleston was gradually shortened, terminating at the portal in 1961 and ceasing entirely in 1962. Previously, Bus 48 ran along Tremont Street to Dudley, with its last run in 1938.

Beyond the Canal Street portal, two routes served Sullivan Square: Bus 92 via Main Street concluded in 1948, and Bus 93 via Bunker Hill Street ended in 1949. Despite these changes, trains continued utilizing this portal and the North Station surface terminal until 1997.

Before becoming Buses 58 and 60, their predecessors split at Brookline; one branch entered current E branch tracks via Boylston Street portal, while the other proceeded along Brookline Street toward Massachusetts Avenue station. These lines were shortened in 1932 to a reduced route from Brookline Village to the subway through Boylston Street portal and ultimately ceased operation in 1938 after being cut back to short-turns at Brigham Circle.

The final "foreign" cars running within the subway system were Eastern Massachusetts Street Railway lines operating from Canal Street portal to Brattle Loop near Scollay Square until 1935. This ended when the Mystic River Bridge closed to streetcars and bus services replaced routes to Chelsea. In 1936, Boston Elevated Railway acquired Eastern Mass Chelsea Division and integrated it with lines connecting at Maverick station through through-routing.

Rolling Stock

Similar to other MBTA subway lines, the Green Line runs on standard gauge rails but employs modern light rail vehicles (streetcars) rather than heavy rail trains, which are incompatible with its surface-level branches that feature numerous grade crossings.

Current Vehicles

Rolling stock :

Year Manufactured	Manufacturer	Model Designation	Image	Length	Width	Fleet Numbers	Count
1986–1988	Kinki Sharyo	Type 7 LRV		72 ft (22 m)	104 in (2.64 m)	3600–3699	100 (78 operational, all refurbished)
1997						3700–3719	20 (15 operational, all refurbished)
1998–2007	AnsaldoBreda	Type 8 LRV		74 ft (23 m)		3800–3894	95 (80 operational)
2018–2020	CAF USA	Type 9 LRV				3900–3923	24 (all operational)

Decommissioned fleet

This list includes only vehicles operated by the MBTA, excluding those from the Boston Elevated Railway period.

Service Period	Manufacturer	Model	Image	Length	Width	Fleet Numbers	Quantity
1976–2007	Boeing Vertol	US Standard Light Rail Vehicle		71 ft (22 m)	104 in (2.64 m)	3400–3543	144 (31 units cancelled)
1937–1985	Pullman Standard	PCC streetcar		48 ft (15 m)	100 in (2.54 m)	3000–3346	344 (2 scrapped before 1964)

Initial rolling stock

The Tremont Street subway, inaugurated in the late 1800s, was intended to allow standard streetcars to avoid downtown traffic congestion rather than function as a complete rapid transit system. Multiple operators merged into the Boston Elevated Railway (BERy), which standardized its fleet on PCC streetcars after evaluating one in 1937. Between 1941 and 1951, BERy procured over 320 PCC units, with an additional order in 1959 to replace aging vehicles. Starting in 1923, all streetcars wore an orange paint scheme for enhanced visibility; this was replaced in 1971 when the MBTA introduced a green and white livery aligned with the Green Line identity.

Two vintage streetcars are preserved on a disused track at Boylston station: Car #5734 (Type 5 A-1, built in 1924), owned by the Seashore Trolley Museum but kept in Boston, and PCC #3295 (built in 1951), under MBTA ownership. These vehicles have occasionally been operated for enthusiast excursions, most recently in 1998.

Boeing Light Rail Vehicle

During the early 1970s, light rail experienced a revival across North America as an economical urban transit solution. In 1971, the Urban Mass Transit Administration (UMTA) appointed Boeing Vertol as systems integrator to develop the "US Standard Light Rail Vehicle" (SLRV), with the goal of unifying light rail vehicle design and encouraging transit expansion.

Boston and San Francisco were selected as pilot cities due to their existing and planned streetcar tunnel infrastructure. The SLRV was engineered to navigate these tunnels and boasted a maximum speed of 50 mph—much faster than the PCC cars—with an articulated center section to boost passenger capacity.

Boeing commenced production of 175 cars for Boston's MBTA in 1973. The initial deliveries began service in December 1976 but were plagued by frequent mechanical problems: derailments on sharp yard curves, battery tray failures, malfunctioning air conditioning units and compressors, unreliable plug-style doors, and early traction motor failures.

In response to these reliability issues, MBTA initiated a refurbishment project in 1977 aimed at extending the service life of older PCC vehicles by rebuilding 34 units from retired stock. As of 2022, some of these refurbished PCC cars continue operating on the Mattapan Line.

Following extended disagreements, MBTA and Boeing reached a settlement in 1979. MBTA declined acceptance of the last 40 SLRVs, while Boeing provided $40 million in compensation to cover repair costs and upgrades.

Contemporary fleet

During the early 1980s, after reaching a settlement with Boeing, the MBTA initiated efforts to procure new vehicles to replace its troublesome LRVs.

In 1980, the MBTA conducted a three-month trial of Canadian Light Rail Vehicles but determined they were unsuitable for Green Line operations. Subsequently, the agency acquired 120 Type 7 LRVs from the Japanese manufacturer Kinki Sharyo, integrating design elements from US SLRVs, Canadian LRVs, and PCC cars. Deliveries comprised 100 units between 1986 and 1988, with an additional 20 arriving in 1997.

Beginning in 1998, the MBTA introduced low-floor Type 8 LRVs produced by Italian firm AnsaldoBreda, ordering 100 cars aimed at enhancing accessibility. The first Type 8 vehicles entered service in March 1999 but encountered significant maintenance difficulties, including frequent breakdowns, derailments at higher speeds, and braking system faults. Owing to these issues, the MBTA canceled the remaining orders in December 2004 under a $225 million contract with Breda. In December 2005, the agreement was restructured to include 85 cars plus spare parts, with payments tied to performance criteria. The last car was completed in December 2006, and ten additional units were delivered late in 2007, totaling 95 cars in operation. The MBTA spent an extra $9.5 million modifying tracks to mitigate derailment risks and initially limited Type 8 operation on the D branch due to speed restrictions.

The final Boeing-Vertol vehicles were retired in March 2007; six were sold to the US Government for testing purposes in Pueblo, Colorado; one was donated to the Seashore Trolley Museum; and three were retained for maintenance duties.

Under a legal settlement reached in 2006, the MBTA committed to running at least one low-floor car per train.

Of the original batch of 120 Type 7 vehicles, 103 underwent refurbishment by Alstom at their Hornell, New York facility. Upgrades included modernized propulsion systems, improved climate control, interior refurbishments, and exterior enhancements. This overhaul initiative began with a pilot car returned in November 2014 and was completed by April 2019.

Type 9

Between 2017 and 2020, twenty-four Type 9 Green Line cars were delivered and began revenue service from late 2018 onward. Full deployment was targeted for fall 2019 but acceptance extended into 2021. These units expand capacity for the Green Line Extension rather than replacing existing vehicles. Manufactured by CAF USA, Inc., the shells and frames were fabricated in Spain with final assembly and testing conducted in Elmira, New York. The first Type 9 car commenced passenger operations on December 21, 2018.

Upcoming fleet

Planning efforts for the Type 10 fleet commenced in 2018 with the objective of replacing all Type 7 and Type 8 vehicles by the mid-2020s using fully low-floor LRVs. At , these new cars will be considerably longer and offer double the passenger capacity compared to current models. The MBTA issued a request for proposals in December 2019 and anticipated issuing a notice to proceed during 2021. In June 2021, an initial order was established for 102 single-car LRVs; procurement of two-car trainsets was deferred pending a federally funded project. Manufacturer bids were due by July of that year.

On August 31, 2022, the MBTA awarded an $811 million contract to CAF USA for delivery of 102 seven-section Type 10 "Supercar" LRVs. Four pilot units are scheduled for delivery in spring 2026, followed by production at a rate of two LRVs per month from spring 2027 through spring 2031. The contract includes options for additional vehicles. Infrastructure improvements supporting this fleet include a comprehensive rebuild of Lake Street Yard, along with upgrades at Riverside Yard and the GLX Vehicle Maintenance Facility. Once Type 10 cars enter service, it is anticipated that the Type 9 fleet will be reassigned to the Mattapan Line, replacing existing PCC streetcars.

Accessibility

The Red Line, Blue Line, and Orange Line utilize rapid transit vehicles operating at high-platform stations, enabling level boarding for passengers with disabilities. Conversely, the Green Line began as a streetcar line that initially operated traditional streetcars before transitioning to light rail vehicles.

Originally, all Green Line stops featured platforms at track level, requiring riders to ascend steps to board, which limited accessibility. To adhere to federal and state mandates, the MBTA introduced several enhancements:

• Manual wheelchair lifts installed at select stations, operated by hand crank; however, their slow deployment often causes delays during rush hours.
• Short elevated platforms accessible via ramps placed near certain stops; due to gaps between doors and platforms, train operators manually deploy bridge plates after trains come to a halt.
• Introduction of low-floor streetcars paired with slightly raised platforms resembling curbs. These vehicles are equipped with remotely controlled bridge plates at center doors to facilitate access for wheelchairs and strollers. As of 2022, the D branch is undergoing comprehensive upgrades including raised platforms as part of this initiative.

History

Boston’s public transit origins trace back to the 1850s with an extensive network of horsecar lines. The state legislature established the West End Street Railway in 1887, which unified multiple lines into a single private system featuring standardized fares and routes. The Allston–Park Square route—later known as the A branch—was the first to adopt electric traction in 1889, employing modified horsecars outfitted with pioneering electrical equipment developed by Frank J. Sprague, first demonstrated in 1888. In 1897, the West End Street Railway leased its assets to the Boston Elevated Railway for a 24-year term before eventually merging.

By the early 1890s, congestion of streetcars in downtown Boston necessitated construction of the Tremont Street subway—the first passenger subway in North America—opened between 1897 and 1898 with stations at Boylston, Park Street, Scollay Square, Adams Square, and Haymarket. The Main Line Elevated utilized this tunnel from 1901 until it was rerouted through its own Washington Street Tunnel in 1908, allowing streetcars to return to Tremont Street.

Originally intended to reduce surface congestion, the Tremont Street subway gradually evolved into a rapid transit corridor. The Causeway Street Elevated and Lechmere Viaduct, completed in 1912, extended grade-separated service to Lechmere Square in Cambridge. The Boylston Street subway opened in 1914 extending westward near Kenmore Square; subsequent expansions included Kenmore station and tunnel extensions completed by 1933. The Huntington Avenue subway, inaugurated in 1941, finalized the removal of surface streetcars from downtown streets.

Beginning in the 1930s, Boston’s widespread surface streetcar network was progressively replaced by buses and trackless trolleys due to lower operational costs and greater route flexibility. By the late 1950s, only five streetcar lines remained: Watertown (A branch), Commonwealth Avenue (B branch), Beacon Street (C branch), Arborway (E branch), along with the Lenox Street Line (43 bus) and some short-turn services. In 1959, the Boston and Albany Railroad’s Highland Branch was converted into the fully grade-separated Green Line D branch (Riverside Line). Service to Lenox Street ceased in 1961; a shuttle operated briefly thereafter. In 1963, part of the original subway underwent reconstruction beneath Government Center, resulting in closure of Adams Square station.

In 1947, following bankruptcy of BERy, the public Metropolitan Transit Authority (M.T.A.) was established but proved unpopular; it was replaced by the Massachusetts Bay Transportation Authority (MBTA) in 1964 with expanded funding aimed at preserving suburban commuter rail. In 1967, remaining streetcar routes were rebranded under the "Green Line" name—reflecting proximity to the Emerald Necklace park system—and designated as lines A (Watertown), B (Commonwealth Avenue), C (Beacon Street), D (Riverside), and E (Arborway).

The Watertown Line operated predominantly in mixed traffic after diverging from Commonwealth Avenue and was permanently replaced by bus service in 1969. The Arborway line beyond Heath Street was converted to bus operation permanently in 1985. Beginning in 2001, introduction of new low-floor streetcars led to station upgrades and major stop renovations for accessibility compliance. In 2004, the Causeway Street Elevated was replaced by a tunnel beneath Boston Garden that unified Orange and Green Lines at a new North Station "superstation," maintaining connections with Commuter Rail services north of Boston.

The designation of "Green Line" in 1967 coincided with MBTA’s comprehensive system-wide branding update. Throughout the 1970s, the Green Line underwent assessment through the Boston Transportation Planning Review focusing on regional effectiveness and modernization plans encompassing infrastructure and operational improvements.

Operations and signaling

As of February 2023, the Green Line's four branches operate with headways ranging from 7 to 9 minutes during weekday peak hours, extending to intervals between 8 and 12 minutes at other times. The fleet in service varies between 45 trains (90 cars) and 62 trains (124 cars).

In contrast to MBTA's heavy rail systems, the Green Line lacks extensive centralized control and monitoring capabilities, which has contributed to slower implementation of countdown displays and "next train" notifications. The line employs advisory wayside signals except where it runs on street-level tracks. These wayside signals are present from Lechmere to the Kenmore portals and cover the entire D–Riverside branch. There are no automatic train protection systems in place; however, vehicles are equipped with electromagnetic track brakes that allow rapid stopping under operator command. Interlockings are controlled using a wayside Automatic Vehicle Identification (AVI) system, requiring operators to input train destinations manually at the start of each run.

Oversight of the line is managed by the Operations Control Center (OCC), with operational control responsibilities shared between the control room and field personnel. Instead of receiving track circuit and signal data directly, operational staff rely on periodic train location updates provided by the AVI system where detection equipment is installed. The OCC interface has transitioned from a text-based format to a schematic display utilizing AVI data. While digital track circuit information exists at Park Street, North Station, and Kenmore interlockings, this data is not transmitted to the OCC. In January 2013, MBTA announced intentions to implement comprehensive vehicle location tracking on the Green Line to support real-time countdown signage and smartphone applications by combining AVI data in tunnels with GPS tracking on surface segments. Real-time location data for surface sections was launched in October 2014, with full system tracking anticipated by early 2015.

The MBTA generally runs two-car trains on the Green Line. One-car trains were last scheduled on weekdays in March 2007. Three-car trains were reintroduced on the B and D branches in 2010 after being absent since 2005; a four-car train underwent testing in April 2011. By March 2011, three-car operations had expanded considerably, including service on the E branch. However, due to operational reliability challenges and slow passenger boarding times, three-car trains were discontinued in March 2016.

Positive train control

In May 2019, MBTA approved an $82.6 million contract for installing a positive train control (PTC) system on the Green Line designed to enforce compliance with red signals and automatically halt trains that approach too closely to others. As of December 2021, the project had reached 28% completion, with plans to install onboard electronics by September 2023, wayside equipment by June 2024, and achieve full operational status by December 2024. A funding reallocation in January 2022 sought to expedite completion to 2023; however, a National Transportation Safety Board report in January 2023 extended the expected timeline to June 2025. Ultimately, MBTA terminated the contract in June 2024 due to insufficient progress and issues with the contractor.

Following this, MBTA engaged a new contractor for the GLTPS-2 system rollout in two phases. Phase 1 aims for deployment by late 2025 on existing Type 7, Type 8, and Type 9 vehicles, providing operators with alerts regarding speed violations and potential collision hazards. Phase 2 is scheduled for completion by June 2028 on Type 9 and forthcoming Type 10 trains, incorporating automatic braking enforcement capabilities. A $112.5 million contract for GLTPS-2 installation was authorized in February 2025.

Turnarounds

In addition to terminal points, several sites incorporate turnaround loops or crossover switches that enable trains to reverse direction for short turn operations. A prominent example includes:

• At , a loop situated beneath City Hall Plaza functions as the downtown endpoint for the B and C branches as of 2022.

Other loops and crossovers, although not frequently utilized during regular revenue service, play roles in construction activities, managing service interruptions, or non-revenue movements. Some have historically operated as terminal points:

• At , pocket tracks facilitate train reversals.
• The Brattle Loop at Government Center allows southbound trains to switch to a northbound direction but is currently reserved for use during disruptions.
• At , a loop links inner tracks; upcoming crossovers are planned to improve capacity and reliability by enabling through movements from the terminating northbound platform.
• At , a loop permits eastbound trains on the C and D branches to reverse westbound.
• Along the B branch, a pocket track at supports bidirectional reversals and is occasionally employed to augment subway service. Additional crossovers are located at , , and east of .
• On the C branch, crossovers at and see occasional use.
• The D branch features crossovers positioned west of , , , , , and ; Reservoir's spur tracks leading to Reservoir Carhouse include platforms designated for short-turn operations.
• The E branch includes crossovers at , , and to aid operational flexibility; notably, the Brigham Circle crossover is frequently utilized for short turns during periods of congestion. A siding at Northeastern also contributes to operational adaptability.

Location tracking

The Red, Orange, and Blue lines employ block signalling systems that facilitate more straightforward tracking of train locations. Beginning in late 2012 through early 2013, most stations on these lines started displaying real-time train arrival information, with data feeds accessible for smartphone applications since 2010. Conversely, the Green Line tunnels and D branch lack this advanced tracking capability due to their signalling infrastructure. In January 2013, the MBTA announced a $13.4 million project funded by MassDOT aimed at implementing comprehensive Green Line tracking by 2015. This initiative leverages existing Automatic Vehicle Identification (AVI), supplemented by additional sensors within tunnels and GPS technology on surface segments.

In September 2013, "Next Train" displays were introduced at Kenmore. By October 23, 2014, location tracking data became available for above-ground Green Line trains, with phased rollouts of arrival predictions and countdown signs continuing into early 2015. By March 2015, sufficient AVI equipment was installed to permit partial release of underground data; most underground tracking was live by August except for areas near Park Street and Boylston stations until September.

The first predictive countdown signs on the Green Line were activated at Newton Centre and Newton Highlands on April 24, 2015, followed by other stations along the D branch. Countdown signs at Kenmore and Hynes became operational in August 2015; subsequently, Copley, Arlington, and eastbound signs from Boylston through Science Park were introduced in October. The final westbound platform signs from Science Park through Boylston were enabled in January 2016. Due to factors such as train holding and short-turning downtown affecting time-based forecasts, these displays indicate how many stops away a train is rather than exact arrival times.

Somerville/Medford extension

The Green Line Extension (GLX) project extended transit service into the northern suburbs of Somerville and Medford. Completed in two stages during 2022, the initiative had a total expenditure of $2.28 billion. The upgraded Lechmere station and the Union Square Branch commenced operations on March 21, 2022, as an addition to the D branch (temporarily designated the E branch). On December 12, 2022, the Medford Branch opened, lengthening the E branch to , with stops at , , , and along the route. Funding sources comprised $0.996 billion from federal funds and $1.28 billion from state allocations. By 2030, daily ridership is anticipated to reach 45,000.

The GLX begins at the northern terminus of the Lechmere Viaduct, incorporating a new elevated track running roughly parallel to Massachusetts Route 28. The previous ground-level Lechmere station was replaced by an elevated facility positioned along this alignment. The two branches separate via an aerial flying junction located on the Red Bridge viaduct within the Inner Belt district: the Union Square Branch extends approximately westward following the Fitchburg Line corridor; meanwhile, the Medford Branch proceeds northwest along the Lowell Line. Both branches are fully grade-separated, eliminating any at-grade crossings. A new vehicle storage yard and maintenance center are situated in the Inner Belt area, accessible from both branches at Red Bridge. Additionally, the Medford Branch features an extension of the Somerville Community Path south of Lowell Street, including a prominent high bridge over the Red Bridge viaduct.

Initially proposed in the 1920s and revisited multiple times thereafter, this extension was mandated in 1990 to offset increased automobile emissions caused by the Big Dig, focusing on serving densely populated and commercially significant neighborhoods in Somerville and Medford near Boston that had been underserved by transit. After delays in planning, Massachusetts committed in 2006 to complete construction by 2014. The 2009 Draft Environmental Impact Report introduced the Union Square Branch; the Medford Branch terminus was designated at College Avenue with a possible future extension to .

The timeline shifted with completion postponed to 2018 in 2011 and further delayed to 2020 by 2014. Construction officially began in December 2012. Initial cost projections were approximately $2.2 billion with half of funding expected from federal sources; however, by 2015 estimates escalated to $3 billion, threatening project feasibility. To reduce expenses, a value engineering review simplified station designs, removed some bridge reconstructions, shortened the Community Path extension, and downsized the maintenance facility. In April 2017, the Federal Transit Administration approved a revised budget of $2.3 billion.

The contract was reissued with options to reinstate six previously excluded features such as canopies, extra elevators, public art installations, a full-scale maintenance facility, and a complete Community Path extension reaching East Cambridge. The winning bid selected in November 2017 incorporated these options. By November 2019, construction was approximately 20% complete; progress advanced beyond 50% by October 2020 and reached about 80% completion by June 2021.

Accessibility renovations

Most of the Green Line was operational by 1959, well before the 1990 enactment of the Americans with Disabilities Act, which mandated comprehensive accessible design. Although the MBTA initiated accessibility improvements on the Red, Orange, and Blue Lines in the late 1980s, upgrades to Green Line stations did not commence until the late 1990s, coinciding with the introduction of Type 8 vehicles. In 1996, the MBTA established the Light Rail Accessibility Program. To control expenses, priority was given to "key stations" characterized by high passenger volumes or significant bus connections.

Around 1998, Riverside station underwent a complete reconstruction featuring raised platforms for accessibility. Stations already equipped with elevators received portable lifts near 2000, including several surface stops. Between 2001 and 2003, raised platforms were installed at sixteen surface stations along the B, C, D, and E branches at a total cost of $32 million. Raised platforms at Park Street and Haymarket were finalized around 2003; Prudential station was rebuilt that same year by the developer of 111 Huntington Avenue. The fully accessible underground "superstation" at North Station opened its doors in 2004. As part of the resolution of Joanne Daniels-Finegold, et al. v. MBTA, eight stations received mini-high wooden platforms for level boarding on older Type 7 LRVs during 2006–07.

Accessibility enhancements progressed with reopening efforts: one station in 2009, two stations in 2010, and another in 2011. After a two-year closure, Government Center reopened in 2016 as an accessible transfer hub. Lechmere was replaced by a fully accessible elevated station in 2022 as part of the Green Line Extension project. Reconstruction of Symphony station is scheduled between 2025 and 2028. Stations currently in design or remaining inaccessible include and . As of 2025, Boylston is not anticipated to be accessible by 2030, while Hynes’ accessibility depends on available funding.

Accessibility improvements on surface branches have steadily advanced. became accessible in 2006, while renovations in 2009 included accessibility upgrades along with lift replacements at and . Brookline Hills completed reconstruction in 2022, and two newly accessible B branch stops ( and ) replaced four previously inaccessible stations in 2021. Temporary accessibility modifications took place at in 2019; all remaining D branch stations received upgrades in 2024, with comprehensive reconstructions planned for later this decade.

Upcoming initiatives target full accessibility for all surface stations:

• The nine remaining non-accessible B branch stops will be rebuilt and consolidated from nine to six stations during 2025–2027.
• Nine non-accessible C branch stations are set for reconstruction and consolidation from nine to seven stops between 2025 and 2026.
• Four non-accessible E branch stations will be rebuilt with consolidation from four to two stops during the period from 2027 to 2029.

Core Capacity Program

During the late 2010s, the MBTA launched a capital initiative aimed at meeting anticipated capacity requirements on the Green Line. A 2018 analysis established the dimensions of the Type 10 vehicles and identified necessary infrastructure enhancements. By 2022, the MBTA progressed into the project development stage under the Federal Transit Administration Capital Investment Grants Program, which supports "core capacity" efforts in heavily utilized transit corridors. As of April 2025, engineering work is scheduled to commence by mid-2025, with complete funding projected by late 2028 and construction continuing into the mid-2030s. The MBTA Board gave approval to the $3.8 billion Core Capacity Program in April 2025, expecting approximately $1.9 billion from federal sources. The main elements include:

• Upgrades to signals, installation of new crossovers, and improvements within the Central Subway
• Systemwide relocation of overhead catenary wires
• Enhancements to traction power along the D Branch
• Yard modifications at Riverside, Reservoir, Lake Street, and Inner Belt facilities
• Accessibility improvements and infrastructure work on the B and E branches
• Acquisition of 58 additional Type 10 vehicles
• Construction of a test track between Chestnut Hill and Newton Centre for Type 10 vehicle testing
• Modernization of a Type 10 operator simulator

Station listing

This table outlines stations on the Green Line segment between and , which is served by multiple branches. Stations exclusive to individual branches are described in their respective branch sections. All stations within the central subway feature prepaid fare zones (fare control).

Fenway–Kenmore

Location	Station	Branches	Opened	Notes and connections
East Cambridge	Disabled access REDIRECT Template:Boston transportation system	D, E	March 21, 2022	Lechmere Viaduct inaugurated June 1, 1912; surface-level station operated July 1922–May 2020. Template:Ric: Template:MBTA bus links Template:Bus icon Template:MBTA other buses
West End	Disabled access REDIRECT Template:Boston transportation system		August 20, 1955
North End	Disabled access REDIRECT Template:Boston transportation system		June 28, 2004	Original surface station operated Sept 3, 1898–Mar 27, 1997; elevated station served June 1, 1912–June 24, 2004. Template:Ric: Template:Ric Template:Ric: Fitchburg, Lowell, Haverhill, Newburyport/Rockport Lines Template:Ric: Template:MBTA bus links Template:Ric: Downeaster Template:Bus icon Template:MBTA other buses
	Disabled access REDIRECT Template:Boston transportation system		September 3, 1898	Template:Ric: Template:Ric Template:Ric: Template:MBTA bus links
Downtown Boston	Disabled access REDIRECT Template:Boston transportation system	B, C, D, E		Template:Ric: Template:Ric Template:Ric: Template:MBTA bus links
	Disabled access REDIRECT Template:Boston transportation system		September 1, 1897	Template:Ric: Template:Ric, Template:Ric (Template:MBTABus) Template:Ric: Template:MBTA bus links At REDIRECT Template:Boston transportation system : Subway Orange; Bus connections
	REDIRECT Template:Boston transportation system			Template:Ric: Silver (SL5) Template:Ric: Template:MBTA bus links
Back Bay	Disabled access REDIRECT Template:Boston transportation system		November 13, 1921	Template:Ric: Template:MBTA bus links
	Disabled access REDIRECT Template:Boston transportation system		October 3, 1914	Template:Ric: Template:MBTA bus links
	REDIRECT Template:Boston transportation system	B,C,D		Template:Ric: Template:MBTA bus links
Disabled access REDIRECT Template:Boston transportation system	October 23 ,1932		Template:Ric : Template:MBTA bus links At REDIRECT Template:Boston transportation system  : Framingham/Worcester Line

Incidents and collisions

On May 28, 2008, a collision between two D branch trains occurred in Newton, Massachusetts, resulting in the operator's fatality and several injuries. The incident was attributed to the driver experiencing micro-sleep caused by sleep apnea.

On May 8, 2009, two trolleys collided rear-end underground near Park Street and Government Center after one operator was distracted by texting. This accident injured 46 passengers and incurred damages estimated at $9.6 million, prompting the MBTA to implement a strict prohibition on cell phone use for its operators.

Two E branch trolleys crashed near Brigham Circle on October 8, 2012, causing injuries to three people including one operator. The following month, a low-speed collision at Boylston station resulted in injuries to several dozen riders.

A derailment of a D branch trolley took place near Kenmore Station on March 10, 2014, leading to ten passengers sustaining moderate injuries and causing an abrupt stop for another train.

In October 2016, The Boston Globe reported that the Green Line experienced the highest number of derailments and collisions among U.S. light rail systems during 2015. This was linked to deferred maintenance on tracks and wheels, which increased occurrences of low-speed derailments involving Type 8 vehicles.

On July 30, 2021, a collision between two B branch trains occurred at , resulting in injuries to 25 individuals.

A train derailed near Lechmere station on October 1, 2024, injuring seven people and suspending Green Line Extension service until October 3. Investigations conducted by the NTSB, Federal Transit Administration, and Massachusetts Department of Public Utilities revealed that the train was traveling at 36 mph within a 10 mph speed-restricted zone, passed a double red signal, and traversed a partially aligned switch, which caused the derailment.

On February 9, 2025, an E branch train collided with an out-of-service train at East Somerville station, resulting in five injuries.

After several accidents, the National Transportation Safety Board recommended implementing positive train control (PTC) on the Green Line in 2009. However, the MBTA rejected this proposal in 2012 due to projected costs ranging from $645 million to $721 million. By 2015, the NTSB expressed concerns over the slow advancement of alternative safety measures. In 2019, MBTA awarded a $170 million contract for a comparable system designed to enforce signals and automatically detect obstacles; this contract was canceled in June 2024. Subsequently, a new contract was granted in February 2025 to deploy a system that will provide operator alerts by late 2025 and enable automatic braking enforcement by mid-2028.

External links

• MBTA – Green Line