39 (MBTA bus)

Massachusetts Bay Transportation Authority (MBTA)

Company type	Public agency
Industry	Public transportation
Predecessor	Metropolitan Transit Authority, Boston Elevated Railway
Founded	1964
Headquarters	Boston, Massachusetts , United States
Area served	Boston, Cambridge, Medford, Somerville, Massachusetts, United States
Products	Public transit services (including Green Line E branch light rail)
Owner	Commonwealth of Massachusetts
Website	www.mbta.com

The E branch—also referred to as the Huntington Avenue branch and formerly known as the Arborway Line—is a light rail route that serves the cities of Boston, Cambridge, Medford, and Somerville within the Massachusetts Bay Transportation Authority (MBTA) Green Line network. This line operates on mixed-traffic street trackage along South Huntington Avenue and Huntington Avenue between and , representing the MBTA’s final revenue service tracks embedded in city streets. Beyond this point, it runs within the median of Huntington Avenue up to before entering the Huntington Avenue subway tunnel. West of , it merges into the Boylston Street subway, continues through the Tremont Street subway to , crosses the Lechmere Viaduct to , and then proceeds along the Medford Branch to . As of February 2023, trains run every eight minutes during weekday peak hours and every eight to nine minutes during off-peak periods, utilizing between 13 and 17 trains (comprising 26 to 34 light rail vehicles).

The line’s origins trace back to horse-drawn streetcar service initiated in 1857 on Centre and South streets in Jamaica Plain. This was followed by Tremont Street service beginning in 1859, forming part of today’s Huntington Avenue corridor extending to Brookline Village, with further expansion along Huntington Avenue occurring from 1881 through 1884. Electrification was implemented by 1891 in Jamaica Plain and completed along Huntington Avenue by 1894. Between 1894 and 1900, multiple branches west of Brookline Village were introduced; both Jamaica Plain and Huntington Avenue routes began utilizing the Tremont Street subway starting in 1897. A connector on South Huntington Avenue opened in 1903, allowing Jamaica Plain service to operate via Huntington Avenue. In the 1920s, Jamaica Plain service extended to , while western branches underwent reconfiguration and were eventually discontinued during the 1930s.

The Huntington Avenue subway tunnel commenced operation in 1941, significantly reducing travel times through the congested Copley Square area. Ownership evolved from Boston Elevated Railway to the Metropolitan Transit Authority in 1947, followed by transition to the MBTA in 1964. The Tremont Street subway was officially designated as the Green Line in 1965, with the Huntington Avenue route becoming known as the E branch two years later in 1967. The early years under MBTA management saw numerous service changes, including a major infrastructure overhaul between 1980 and 1982. In 1985, service beyond Brigham Circle was replaced by route 39 bus—a change initially intended as temporary but ultimately made permanent—although service to Heath Street resumed in 1989 after street track work on Huntington Avenue. The downtown terminal location shifted multiple times; from 1987 until 2020 it was predominantly Lechmere station. In May 2020, the E branch was truncated to North Station due to construction of the Green Line Extension, briefly extended to in March 2022, and then permanently extended to Medford/Tufts by December of that year.

Horsecar lines

The E branch has its roots in several early streetcar lines, beginning with the West Roxbury Railroad—a horsecar operation inaugurated on November 14, 1857, serving West Roxbury. This line ran from to Jamaica Plain via Lowell Street (now Columbus Avenue), Centre Street, and South Street. The Metropolitan Railroad leased this line and provided continuous service connecting Jamaica Plain with downtown Boston over Tremont Street. The journey took over an hour at a fare of ten cents. At Jamaica Plain’s terminus on Jamaica Street stood a two-track carhouse equipped with a waiting room; meanwhile, the Metropolitan Railroad’s primary carhouse was located at Roxbury Crossing. In 1858, a connection was established linking Lowell Street to John Eliot Square, enabling cars from Jamaica Plain to access downtown Boston via Washington Street (passing through ). That same year featured infrastructure improvements such as double-tracking certain sections.

On August 1, 1859, permission was granted for a new branch extending northwest of Brookline Village along Washington Street to School Street. This branch opened on October 26, 1859; double-tracking authorization followed in 1879. The segment west of Brookline Village may have operated sporadically.

With Back Bay’s expansion, Huntington Avenue emerged as an important transit corridor. On March 18, 1881, the Metropolitan Railroad secured rights for constructing a double-track line on Huntington Avenue stretching from Copley Square—where it connected with the Marlborough Street line—to West Chester Park (later renamed Massachusetts Avenue). By September of that year, this route was operational and served events at Mechanics Hall and the New England Fair Building. An extension from West Chester Park reaching Brigham Circle opened on October 1, 1884, establishing a second connection between Brookline and Boston. Around late 1884, a branch launched along Longwood Avenue reaching . Circa 1888 saw another branch extend westward from Brookline Village along Boylston and Cypress Streets into Pill Hill—likely intended as competition against the Boston and Albany Railroad’s Newton Circuit service through Brookline that had begun in 1886.

Electrification

In November 1887, the Metropolitan was absorbed by the West End Street Railway, uniting Boston's streetcar systems into a single network. After successfully electrifying the Beacon Street line during 1888–89, the West End quickly transitioned its entire system to electric power. The Jamaica Plain–Northern Depots route switched to electric service on October 14, 1891, with other Tremont Street lines following soon after. The horsecar barn at Jamaica Plain was replaced initially by an electric carhouse and then, in early 1901, by a larger facility capable of housing 150 streetcars along with passenger conveniences.

Between 1893 and 1894, the West End electrified the Huntington Avenue line, completing most of the work by mid-July except near the Riverway. On August 4, all Brookline routes via Huntington Avenue shifted to electric operation, including branches along Washington Street (extended to Park Street), Cypress Street, and Tremont Street tracks leading to Roxbury Crossing. The Washington Street branch was extended to Beacon Street at on September 1, enabling continuous service between Reservoir and Brookline Village. On August 15, 1896, the Beacon Street line was lengthened along Chestnut Hill and Commonwealth Avenues to Lake Street, linking with the Commonwealth Avenue Street Railway.

In November 1894, the Cypress Street branch reached a new carhouse accommodating 36 streetcars; this facility was expanded in 1897 to hold about 79 vehicles. Electrification of the Longwood Avenue branch was completed in 1894–95 but only covered the Boston portion due to infrastructure limitations and Brookline’s mandate to remove tracks west of its boundary. Between 1894 and 1896, Huntington Avenue was upgraded into a boulevard with streetcar tracks relocated into a dedicated median east of Brigham Circle.

The initial segment of the Tremont Street subway opened on September 1, 1897. Lines entering the subway via the Public Garden incline included routes on Cypress Street through Huntington Avenue as well as Jamaica Plain crosstown services. The southern portion of the subway extending to the Pleasant Street incline opened on September 30, routing Jamaica Plain cars along Tremont Street into the subway. Service from Reservoir via Huntington Avenue began on November 8, followed shortly by Longwood Avenue and Lake Street cars. Additional early routes using Huntington Avenue east of Massachusetts Avenue included Forest Hills–Park Street and Humboldt Avenue–East Boston Ferries lines introduced in the late 1890s and early 1900s.

Expansion

Two connecting lines commenced operations in August 1900. Newly laid tracks on Harvard Street from Brookline Village to allowed through service from Allston into the subway via Huntington Avenue. The Ipswich Street line introduced a route between Brookline Village and the subway, initially terminating at Cypress Street. Ipswich Street service extended westward along Boylston Street to Chestnut Hill Avenue on September 29, 1900, reaching the Newton line at Chestnut Hill by November 19. Through service on Longwood Avenue ended on August 8, 1901, replaced by a shuttle between Brookline Avenue and Huntington Avenue. On May 5, 1903, the Boston and Worcester Street Railway (B&W) began operations initially terminating at Chestnut Hill but extended over BERy tracks along Boylston Street and Huntington Avenue to Park Square by July 6.

The Main Line Elevated started service between and on June 10, 1901, utilizing outer Tremont Street subway tracks and offering a quicker downtown connection than surface streetcars. This development prompted rerouting Jamaica Plain service to Dudley Square transfer station and establishing a Dudley–Brookline route. Track construction on South Street between Jamaica Plain and Forest Hills Square was approved in June 1900; work began in April 1902 with service commencing May 17. In May 1903, Boston Elevated Railway installed tracks on South Huntington Avenue between Centre Street and Huntington Avenue and launched Jamaica Plain–Park Street service via this corridor.

By March 1907, regular Huntington Avenue routes west of Massachusetts Avenue included cars from Jamaica Plain via South Huntington Avenue; Lake Street via Washington Street; via Harvard Street; and Allston Carhouse via Harvard Street—all entering the subway and looping at Park Street—as well as Cypress Street–Dudley cars and B&W services. Additional routes utilized South Street and Center Street tracks in Jamaica Plain such as Forest Hills–Park Street (via Columbus Avenue), Jamaica Plain Carhouse–Dudley, and Jamaica Plain–. Some Allston–Park Street cars were rerouted along Longwood Avenue on October 12, 1907, replacing the shuttle operation.

On November 30, 1908, Main Line trains were diverted into the Washington Street Tunnel; outer Tremont Street subway tracks reopened for streetcars on December 4 with some lines extended or rerouted from Dudley. Streetcars entering the subway via Boylston Street looped at Park Street; those entering at Pleasant Street (including lines from Brookline via Tremont Street and Jamaica Plain via Roxbury Crossing) exited at Canal Street and looped at .

The Washington Street Elevated reached on November 22, 1909, increasing its role as a transfer hub. Local demands for extending South Huntington Avenue line from Jamaica Plain Carhouse to Forest Hills began before completion and persisted through the following decade. Free transfers at Jamaica Plain Carhouse were introduced on March 1, 1913. In April that year, BERy considered express service for South Huntington Avenue but lacked sufficient cars for extension. On June 12, 1915, the Hyde Park–Forest Hills line was extended to Jamaica Plain Carhouse; meanwhile Forest Hills–North Station (via Columbus Avenue) service was truncated there to improve frequency between Forest Hills and the carhouse. Due to low popularity, Hyde Park service reverted back to Forest Hills on October 2, 1915; concurrently the Charles River line was extended to connect West Roxbury directly with South Huntington Avenue.

On March 1, 1924, BERy inaugurated a streetcar transfer station within Arborway Yard to relieve congestion at Forest Hills station. Shortly thereafter, South Huntington Avenue line was extended to Arborway enhancing connectivity with other routes.

Reroutes and buses

Beginning January 25, 1913, the Allston–Brookline Village–Park Street routes were extended to reach North Station, allowing continuous service between Back Bay and North Station. On May 24, 1914, the BERy inaugurated the Allston–Dudley crosstown route via Brookline Village. The Boylston Street subway commenced operations on October 3, 1914, extending westward to Kenmore Square and substituting the Public Garden Incline with a portal located in the median of Boylston Street for Huntington Avenue and Ipswich Street services. During this timeframe, Washington Street service experienced terminal modifications, involving several route reductions and subsequent reinstatements through 1915.

By 1921, the Huntington Avenue corridor supported four subway services: Lake Street, Jamaica Plain, Longwood, and Opera Place short turns. BERy suggested operating the line as a semi-rapid transit system featuring two-car trains between Brookline Village and Park Street, with single-car shuttles on other segments. However, opposition from Jamaica Plain residents resulted in adjustments; starting February 6, 1922, two-car trains ran between Brookline Village and Park Street while Washington Street functioned as a shuttle between Brookline Village and Lake Street.

In June 1925, Ipswich Street service was truncated to Massachusetts–Chestnut Hill, terminating direct Chestnut Hill–downtown Boston connections; this was reversed in March 1926 by swapping terminals with Huntington Avenue trains. Evening peak express service on South Huntington Avenue cars began in December 1928. The Longwood Avenue shuttle transitioned to bus operation in June 1925 and ceased entirely in 1942; transit service along Longwood Avenue resumed only with route 47 in 1972. The Washington Street shuttle converted to bus service on April 24, 1926—later designated as route 65—and its rails were dismantled during World War II.

The Worcester Turnpike’s paving as Massachusetts Route 9 during the 1930s prompted removal of streetcars; buses replaced Boston and Worcester Street Railway cars on June 11, 1932. By November of that year, paving had reached Chestnut Hill, leading to truncation of Huntington Avenue cars to Cypress Street and Ipswich cars to Brookline Village, supplemented by a bus route linking Chestnut Hill and Brookline Village. By mid-1933, Ipswich Street operated as a shuttle supported by a new Brookline Village–Kenmore bus route. The Cypress Street Carhouse closed on December 3, 1933.

On June 10, 1934, service was cut back from Cypress Street to Brookline Village with buses covering the segment between Cypress Street and Kenmore. These routes underwent multiple changes before consolidating into MBTA bus route 60 in 1985. The Allston–Dudley line was replaced by bus service on September 10, 1938; Brookline Village cars were shortened to Brigham Circle short turns. The transfer station at Brookline Village was promptly demolished to enhance traffic flow.

Huntington Avenue subway

Proposals for a subway along the Huntington Avenue line date back to 1906, aimed at removing streetcars from congested sections of Boylston Street and Copley Square. At that time, streetcars operated mixed with regular traffic on these stretches except for a dedicated median west of Dartmouth Street on Huntington Avenue. In 1911, a subway extending as far as Mechanics Hall was proposed but rejected in 1912 due to expectations that the newly opened Cambridge and Boylston Street subways would halve streetcar volumes on Boylston Street.

In May 1924, the state legislature tasked the Metropolitan District Commission with planning an expanded rapid transit network for Boston that included extending the Boylston street Subway beneath Governors Square. A December 1926 report recommended reorganizing current streetcar tunnels into two rapid transit lines using high-floor vehicles. One proposed line would run from Lechmere through the Tremont Street subway alongside New Haven Railroad tracks toward Providence before surfacing along Huntington Avenue up to Francis Street (Brigham Circle). Planned new stations included Pleasant Street, Back Bay, West Newton Street, and Massachusetts Avenue, with consolidated stops at key locations. Surface streetcar connections were envisioned at Brigham Circle. Future extension toward Brookline Village was also considered.

Following closure of the Berkeley Street line around 1930, only Huntington Avenue cars utilized the Boylston Street Incline. In June 1932, legislation authorized construction of a tunnel from Gainsborough Street beneath Huntington Avenue and adjacent streets to Park Street station; however, BERy declined this plan due to redundancy with existing subways and prohibitive costs—the legal mandate prevented altering the proposed route.

Mayor James Michael Curley proposed an $8.5 million subway from Copley Square to Longwood Avenue in 1933 funded through the National Industrial Recovery Act rather than local borrowing. Later that year, state legislation granted greater flexibility in routing options; consequently, six tunnel plans varying in length and alignment were evaluated by the Boston Transit Department.

In October 1936, approval was granted for constructing a subway extending just short of West Newton Street as part of a federal Works Progress Administration (WPA) initiative costing $1.715 million with $539,000 contributed by the city. Plans received endorsement from both Boston City Council and Boston Elevated Railway in April 1937; construction commenced on September 18 of that year. In 1938, project scope extended to Opera Place including underground stations at key points plus an automobile underpass near Massachusetts Avenue adjacent to Symphony station; federal approval followed in August.

The twin-tube tunnel stretched approximately long; tubes ran side-by-side except at Symphony station where they flanked an underpass. Final expenses totaled $7.13 million (equivalent to $ today), with $1.93 million from city funds and $5.20 million federally sourced—making it second only to LaGuardia Airport among WPA-funded projects.

The Huntington Avenue subway opened on February 16, 1941, relocating most Huntington Avenue cars underground along their route. Three lines operated via this subway:

• 39: –

  Jamaica Plain–

• 57: Francis Street (Brigham Circle)–Park Street (a short turn variant of route 39)

A loop at was constructed in 1945 to accommodate new PCC streetcars featuring operator cabs at one end only; route 57 extended there on December 15 that year using PCC cars starting January 3, 1946. Between June 1947 and June 1949—and again during the 1950s—a shuttle ran between Northeastern University and Park Street.

Route 41 transitioned fully to buses on June 8, 1949. In 1954 route 57 extended service to its surface terminal at . By September 1, 1961—when route 57 had become weekday-only—it was discontinued; its number was reassigned later that year for a brief Boylston–Pleasant Street shuttle service. From September 1962 until March 1965 a single morning peak round trip operated between Lechmere and Heath Street catering to school demand—the only occasion when three-car PCC trains ran along Huntington Avenue.

MBTA era

In 1964, the Massachusetts Bay Transportation Authority (MBTA) took over from the MTA and introduced a color-coded system for subway lines the following year, designating the Tremont Street subway as the Green Line. On December 26, 1964, a new loop at Government Center enabled short-turn trips to Heath Street to serve the Prudential Center, but this service was reduced back to Park Street the next month before being reinstated to Government Center on March 25, 1967. Peak-period Heath Street short turns were increased on September 19, 1966, but discontinued by November 7. On January 3, 1972, two-car short turns to Heath Street were scaled back to single-car operations.

In 1967, each of the five Green Line branches was assigned a letter designation, with Huntington Avenue becoming the E branch. Planning commenced in 1968 for widening Huntington Avenue east of Brigham Circle, which involved closing three stops—Forsyth Street, Vancouver Street, and Wigglesworth Street—and expanding platforms at the remaining five stations. The project also entailed relocating a siding and installing fencing between tracks to enhance safety. However, progress was hindered by federal budget reductions in 1969. Track replacement work between Brigham Circle and Parker Hill Street took place in 1971, and the widening initiative resumed in 1972 with proposals for a pedestrian bridge at Northeastern University. Opposition from the Museum of Fine Arts regarding land use caused further delays, and the project was eventually suspended during the mid-1970s economic downturn.

Between September 11, 1976, and January 1, 1977, nighttime service on the Huntington Avenue subway was replaced with buses to facilitate lighting and electrical system upgrades. Due to a shortage of cars during winter, peak and midday service was curtailed to Heath Street on January 1; route 39 buses operated between Arborway and Copley until March 19. Regular Heath Street short turns extended service to North Station until June 18; from June 18 to September 9, buses again substituted weekday service beyond Heath Street for track maintenance. Ongoing streetcar shortages combined with delays in delivery of new Boeing LRVs resulted in weekday bus replacements past Heath Street beginning October 17, 1977; full Arborway service was restored on December 31, 1978. The new LRVs were introduced starting January 16, 1978—initially serving Northeastern short turns and later extended to Heath Street by April.

Although the originally planned road widening was never implemented, the MBTA rebuilt the line to accommodate LRVs during simultaneous road and sewer construction along Huntington Avenue. This reconstruction followed earlier plans but omitted the Northeastern footbridge. Three proposed stops along with Parker Street station were eliminated; meanwhile, stations at Brigham Circle, , Museum-Ruggles, and Northeastern were reconstructed with expanded platforms. On March 21, 1980, service was truncated to a Symphony–Park Street LRV shuttle with route 39 buses replacing service beyond Symphony. The shuttle was extended first to Northeastern on June 21 and then to Brigham Circle on September 20. Symphony station closed on January 3, 1981 due to budget cuts; restoration of outer line service was delayed by financial challenges but Arborway service resumed on June 26, 1982—this included peak-period Heath Street short turns and reopening Symphony station.

Heath Street service was extended to Lechmere on January 2, 1983. A snowstorm in February temporarily halted Arborway Line operations; a Lechmere–Government Center shuttle replaced Heath Street cars until March 26. From October through November of that year, construction near Arborway caused service to be cut back to , with route 39 buses providing replacement service. Heath Street short turns using LRVs recommenced on September 18, 1984.

Controversy over Arborway restoration

On December 28, 1985, the Arborway Line was indefinitely discontinued and replaced by the route 39 (Arborway–) bus service due to construction work on Huntington Avenue. This change marked the end of PCC streetcar operations on the Green Line, although PCC cars continued running on the Mattapan Line. Light Rail Vehicle (LRV) service was reinstated to Brigham Circle on July 26, 1986, with weekday terminals at Lechmere and weekend and evening terminals at Government Center. By June 20, 1987, all trips to Brigham Circle were extended to Lechmere utilizing newer Type 7 LRVs. Service to Heath Street resumed on November 4, 1989; however, buses continued to operate south of Heath Street. In December of that year, route 39 was extended to Back Bay station to facilitate transfers to the Orange Line, accompanied by a fare reduction to match bus prices. By 1990, route 39 had become the MBTA’s busiest bus corridor, serving approximately 19,040 passengers daily. Between 2000 and 2017, buses operated using a loop originally constructed for Green Line trains but never utilized by them.

The proposal to reinstate E branch streetcar service to Arborway generated significant debate. Residents of Jamaica Plain supported the restoration, whereas the MBTA opposed resuming the extended section of street-running track. A study conducted in 1987 estimated restoration costs at $37.4 million for construction and $5.9 million annually for operations but anticipated that ridership would surpass that of bus service. To settle a lawsuit brought by the Conservation Law Foundation, the Massachusetts Executive Office of Transportation and Construction (EOTC) agreed to implement environmental mitigation measures associated with the Central Artery/Tunnel Project. The resulting Administrative Consent Order (ACO) in 2000 mandated restoring streetcar operations beyond Heath Street extending to Arborway. This requirement was also incorporated into the State Implementation Plan to comply with Clean Air Act air quality standards. Following opposition from both the MBTA and local community organizations, a revised settlement replaced localized E branch restoration with alternative regional transit improvements. The EOTC pledged to explore other transit enhancement options within the Arborway corridor.

A study published in 2004 emphasized that maintaining street-running tracks along South and Centre streets would exacerbate traffic congestion and risk obstructing emergency vehicle access. In March 2005, Councilor John Tobin formally requested removal of the tracks due to severe infrastructure degradation rendering them unusable. The Arborway Committee’s lawsuit filed in 2007 was dismissed as untimely in January 2011, effectively halting restoration efforts. By late 2023, the MBTA had removed roughly 140 remaining overhead wire poles associated with this line. Meanwhile, the City of Boston has proposed extending the E branch further southward toward Hyde Square in Jamaica Plain.

During the Orange Line closure from August through September 2022, dedicated bus lanes were introduced on several Boston streets served by route 39. Four segments—Boylston Street (from Ring Road to Clarendon), Clarendon Street (Boylston to Columbus), St. James Avenue (near Berkeley Street to Dartmouth Street), and Huntington Avenue (Brigham Circle to Gainsborough)—were subsequently made permanent. Data released by the MBTA in September 2023 indicated that dedicated lanes along Huntington Avenue reduced travel times by up to two minutes during peak periods.

In May 2022, the MBTA’s preliminary draft for its network redesign suggested extending route 39 through via and , replacing portions of routes , , and , while discontinuing service between Longwood Avenue and Back Bay. However, a revision issued in November 2022 restored route 39’s existing alignment and introduced an extended and more frequent route 47 serving Union Square.

Subsequent modifications

On October 20, 1996, flooding caused by the Muddy River interrupted service on the central subway, resulting in a temporary substitution of the E branch with bus service. Restoration occurred in stages: service resumed to Northeastern by October 25, extended to Brigham Circle on November 9, and finally reached Heath Street by December 7. Between July 24 and December 17, 2000, the line was truncated to Brigham Circle due to track maintenance along South Huntington Avenue, with express buses operating as a supplement.

During the early 2000s, the MBTA undertook accessibility improvements by upgrading major surface stops with raised platforms under the Light Rail Accessibility Program. Temporary portable lifts were installed at Heath Street around 2000. In mid-2002, weekend rail services were replaced by buses while station construction was underway. By 2003, accessible platforms had been completed at Northeastern, Museum of Fine Arts, Longwood, Brigham Circle, and Heath Street stations—a $32 million project encompassing thirteen stations across the B, C, and E branches. The Prudential station's accessibility enhancements coincided with adjacent development at 111 Huntington Avenue during 2002–03.

From June 28, 2004, through November 12, 2005, E branch operations were shortened to terminate at due to the replacement of the Causeway Street elevated with a new underground tunnel. Additional track work prompted another reduction of service to Brigham Circle from September to December 2006. Starting March 21, 2011, three-car trains briefly ran on the line. Service was again curtailed to North Station from April to November 2011 during renovation activities at .

Budget constraints led to weekend service being cut back to Brigham Circle on July 1, 2012—a decision that faced opposition from local communities. This reduction was quietly reversed on October 13, 2012, by slightly lowering frequency while maintaining full-line coverage without additional costs; this adjustment was officially incorporated into the December timetable.

Between August 3 and 29 in both 2020 and 2021, segments between Prudential–Heath Street and Heath Street–Brigham Circle were closed for accelerated track and grade crossing replacements totaling approximately . In 2023, accessibility modernization began at Symphony station but was suspended in 2024 due to bids exceeding budget expectations.

On May 24, 2020, service was truncated from Lechmere to North Station to allow demolition of the former Lechmere Elevated structure and enable connection of the Lechmere Viaduct with the Green Line Extension (GLX). The initial GLX plan assigned the E branch extension to Union Square; however, by April 2021 the MBTA reassigned the E branch extension to Medford/Tufts and designated Union Square service for the D branch. This arrangement took advantage of both branches’ proximity to the Longwood Medical Area, with the E branch allocated to the longer Medford route due to its shorter western segment.

The Union Square Branch officially opened as part of the E branch on March 21, 2022. From August 6 through August 20, 2022, service between Heath Street and Copley was suspended for track replacement and installation of a train protection system; during this period Union Square was served exclusively by C and D branches. The section between Union Square and Government Center was closed from August through September for final integration of the Medford Branch and removal of speed restrictions on the Lechmere Viaduct. After reopening, both D and E trains began serving Union Square. On November 1, Lechmere became the terminal station for the E branch while test trains continued out-of-service runs to Medford/Tufts; revenue service on the Medford Branch commenced on December 12, 2022.

In 2021, plans were announced to upgrade the Heath Street–Brigham Circle corridor by replacing existing stops with accessible platforms designed for two Type 10 vehicles. Design efforts started in July 2023. New platforms will be constructed at Riverway and Mission Park stations; meanwhile Fenwood Road and Back of the Hill stops will be discontinued. As of December 2024, design completion is anticipated before year-end with construction scheduled between 2027 and 2029. The project’s estimated cost stands at $86 million.

Station listing

Location	Station	Opened	Notes and connections
Medford	REDIRECT Template:Boston transportation system	December 12, 2022	Template:Ric: Template:MBTA bus links
	REDIRECT Template:Boston transportation system		Template:Ric: Template:MBTA bus links
Somerville	REDIRECT Template:Boston transportation system
	REDIRECT Template:Boston transportation system		Template:Ric: Template:MBTA bus links
	REDIRECT Template:Boston transportation system		Template:Ric: Template:MBTA bus links
East Cambridge	REDIRECT Template:Boston transportation system	March 21, 2022	The Lechmere Viaduct initially opened on June 1, 1912, featuring a direct surface line connection until July 9, 1922. A surface station operated from July 10, 1922, through May 23, 2020. Template:Ric: Template:MBTA bus links Template:Bus icon Template:MBTA other buses
West End	REDIRECT Template:Boston transportation system	August 20, 1955
North End	REDIRECT Template:Boston transportation system	June 28, 2004	Template:Rint Amtrak: Template:Lnl Template:Ric: Fitchburg Line, Lowell Line, Haverhill Line, Newburyport/Rockport Line Template:Ric: Template:Ric Template:Ric: Template:MBTA bus links Template:Bus icon Template:MBTA other buses The original surface station was in service from September 3, 1898 until March 27, 1997; the elevated station operated from June 1, 1912 to June 24, 2004.
	REDIRECT Template:Boston transportation system	September 3, 1898	Template:Ric: Template:Ric Template:Ric: Template:MBTA bus links
Downtown Boston	REDIRECT Template:Boston transportation system		Template:Ric: Template:Ric Template:Ric: Template:MBTA bus links
	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: Template:Ric (Template:MBTABus) Template:Ric: Template:MBTA bus links
Back Bay, Boston	REDIRECT Template:Boston transportation system	November 13, 1921	Template:Ric: Template:MBTA bus links
	REDIRECT Template:Boston transportation system	October 3, 1914	Template:Ric: Template:MBTA bus links
	REDIRECT Template:Boston transportation system	February 16, 1941	Template:Ric: Template:MBTA bus links
Fenway–Kenmore	REDIRECT Template:Boston transportation system		Template:Ric: Template:MBTA bus links
	REDIRECT Template:Boston transportation system	August 4, 1894	Template:Ric: Template:MBTA bus links
	Forsyth Street		Closed March 22, 1980
	Parker Street		Closed March 22, 1980
	Vancouver Street		Closed March 22, 1980
	rowspan=3 Longwood Medical Area		Template:Bts Longwood Medical Area	Template:Ric MBTA Bus name=y: LMA
Wigglesworth Street	Closed March 22, 1980
Template:Bts Brigham Circle	Template:Ric MBTA Bus name=y: Brigham Circle
rowspan=5 Mission Hill	Template:Bts Fenwood Road		Template:Ric MBTA Bus name=y: Fenwood Road
Template:Bts Mission Park	Template:Ric MBTA Bus name=y: Mission Park
Template:Bts Riverway	Template:Ric MBTA Bus name=y: Riverway
Template:Bts Back of the Hill	June 26, 1982		Template:Ric MBTA Bus name=y: Back of the Hill
Template:Bts Heath Street	December 15, 1945	Template:Ric MBTA Bus name=y: Heath Street
\bgcolor="lightgray"; rowspan="4" Jamaica Plain	'Stops on South Huntington Avenue'	\bgcolor=lightgray July 11,1903	Closed December 28,1985
'Stops on Centre and South Streets'	\bgcolor=lightgray October14,1891
'Stops on South Street'	\bgcolor="lightgray"; rowspan="2" May17,1902
\bgcolor=lightgray; Arborway	\bgcolor=lightgray Closed December28,1985 Terminal for streetcar (until1953) and bus lines. Connection to Orange Line at Forest Hills station (MBTA)

External links

• MBTA – Schedule for Green Line E
• City of Boston – Enhancements for E-Branch Accessibility and Multimodal Corridor