Green Line "B" Branch
The "B" Branch, also called the Commonwealth Avenue Branch or Boston College Branch, is a branch of the Massachusetts Bay Transportation Authority Green Line in the Boston, Massachusetts area, along which light rail vehicles run on a surface right-of-way down the middle of Commonwealth Avenue. After going underground via the Blandford Street Incline, the tracks merge with the "C" and "D" Branches into Kenmore station. From there the Boylston Street Subway and Tremont Street Subway carry "B" cars to downtown Boston, with regular service turning around at Government Center. The "B" Branch gives its name to the Green Line Rivalry between Boston College and Boston University, both of which are located on the line.
In 1896, tracks were laid on Commonwealth Avenue from Chestnut Hill Avenue west to the Newton town line at Lake Street, and around the same time the Commonwealth Avenue Street Railway opened, extending the tracks through Newton to Norumbega Park; this later became part of the Middlesex and Boston Street Railway. Trains between Lake Street and downtown Boston used tracks on Beacon Street, now part of the "C" Branch. From Kenmore Square they continued east on Beacon Street, then turned south on Massachusetts Avenue and east on Boylston Street to Park Square. In 1900 tracks were installed on the rest of Commonwealth Avenue, from Chestnut Hill Avenue east to existing tracks at Packard's Corner, later part of the "A" Branch. This enabled trains to use Commonwealth Avenue between Lake Street and Kenmore Square. In 1909, the tracks were electrified.
The Tremont Street Subway opened on September 1, 1897, and then or soon after the Commonwealth Avenue line was rerouted to turn around at Park Street via the Boylston Street Incline at the Public Garden. The Boylston Street Subway opened on October 3, 1914, extending the underground portion to the Kenmore Incline just east of Kenmore Square. On October 23, 1932 the Blandford Street Incline opened along with the underground Kenmore station, giving the line its present configuration.
Until the 1920s, a streetcar line that has since become the 65 bus ran along Commonwealth Avenue from Boston College east to Chestnut Hill Avenue, then south on Chestnut Hill Avenue and east on Beacon Street from Cleveland Circle to Washington Square, turning southeast to Brookline Village. After this was replaced by bus service in the 1920s (along with a rerouting), no revenue service used the tracks on Chestnut Hill Avenue, but they have remained for "B" Branch trains to access the Reservoir Carhouse at Cleveland Circle on the "C" Branch.
A turnback loop at Boston University Field was present from 1915 to January 14, 1962. It was used for service to special events as well as to short-turn some rush hour trains.
From 1942 to 1967, the route was known by the map number of 62. In 1967, the lines were given colors and the Green Line branches were lettered. The Commonwealth Avenue Line became the "B" Branch.
Downtown terminal 
Until 1931, the line always looped at Park Street. On February 7 of that year, the Commonwealth Avenue service was extended east through downtown to loop at Lechmere. Since then, the following changes in east terminal have been made:
- November 20, 1961: cut back to Park Street
- November 18, 1964: extended Monday-Saturday to Government Center
- January 1967: cut back to Park Street all times due to problems at the Government Center loop
- March 25, 1967: extended to North Station
- June 17, 1967: cut back to Government Center
- September 9, 1967: extended to North Station
- September 14, 1967: cut back to Government Center due to problems at the North Station loop
- March 21, 1970: extended to Haymarket, looped empty at North Station
- December 26, 1970: extended to North Station
- March 25, 1974: extended to Lechmere
- January 1, 1977: cut back to North Station weekdays only
- March 19, 1977: extended to Lechmere all times
- June 18, 1977: cut back to Government Center all times
- September 9, 1977: extended to Lechmere all times
- September 9, 1978: cut back to Government Center nights and Sundays
- March 24, 1979: cut back to Government Center middays and Saturdays, with only rush hour trips continuing to Lechmere
- March 21, 1980: cut back to Park Street all times
- April 4, 1981: extended to North Station (PCC cars looped at Government Center)
- July 30, 1983: cut back to Government Center
The B Branch is frequently criticized by riders for its slow service. It is markedly slower than the C branch, in part because of its greater density of stops and at-grade crossings. Both B and C line branches are slower than the D branch, which has the lowest stop density and a dedicated right-of-way.
In late 2003, the MBTA proposed eliminating five stops along the branch (Greycliff Road, Mount Hood Road, Summit Avenue, Fordham Road, and Chiswick Road.) This was seen as a way to speed up service for riders, while also reducing the MBTA's maintenance costs. Many riders welcomed the change, noting the stops' low ridership and close proximity to more popular stops. Others felt that the change did not go far enough, noting that the total time savings would be small (a few minutes out of a 45-minute trip) and the B branch would still be the slowest Green Line branch by far. Many riders questioned why the MBTA did not propose closing any of the stops east of Packard's Corner, even though this would improve travel times for the largest number of riders and several of these stops are only several hundred feet apart.
In April 2004, four of the five stops (Greycliff Road, Mount Hood Road, Summit Avenue and Fordham Road) were closed in a pilot stop elimination program. The fifth (Chiswick Road) was spared, after elderly residents of the nearby Jewish Community Housing facility rallied to its defense. In 2005, after a survey showed that 73% of 1,142 riders surveyed approved of the closures, the MBTA announced that the four stops would be closed permanently. Despite these favorable and popular results by B branch riders, the MBTA maintains no further plans to improve service times on the B branch, either by reducing stop frequency or using any other means.
Station listing 
Trains on the 'B Line' only travel from Government Center to Boston College. The segment from Government Center to Kenmore is shared with the three other branches. There is no MBTA parking at any "B" branch stations. All stations between Kenmore and Packard's Corner are also stops of the 57 bus to Watertown.
|Station||Location||Time to Park Street||Time to Lechmere (must change to 'E Line' train)||Time to Boston College||Transfers and notes|
|Blandford Street||Commonwealth Avenue at Silber Way, Boston||16 minutes||29 minutes||27 minutes|
|Boston University East||Commonwealth Avenue at Granby Street, Boston||17 minutes||30 minutes||26 minutes|
|Boston University Central||Commonwealth Avenue at Marsh Chapel, Boston||18 minutes||31 minutes||25 minutes|
|Boston University West||Commonwealth Avenue at Amory Street, Boston||19 minutes||32 minutes||24 minutes|
|St. Paul Street||Commonwealth Avenue at Buick Street, Boston||20 minutes||33 minutes||23 minutes|
|Pleasant Street||Commonwealth Avenue at Pleasant Street, Boston||22 minutes||35 minutes||21 minutes|
|Babcock Street||Commonwealth Avenue at Babcock Street, Boston||24 minutes||37 minutes||19 minutes|
|Brighton Avenue/Packard's Corner||Packard's Corner at Brighton Avenue, Allston||26 minutes||39 minutes||17 minutes||the "A" Branch formerly diverged here|
|Fordham Road||Commonwealth Avenue at Fordham Road||No longer a stop||Closed in 2005 to ease travel time.|
|Harvard Avenue||Commonwealth Avenue at Harvard Avenue, Allston||28 minutes||41 minutes||15 minutes||#66 Bus Also known as King's Corner.|
|Griggs Street/Long Avenue||Commonwealth Avenue at Griggs Street, Allston||30 minutes||43 minutes||13 minutes|
|Allston Street||Commonwealth Avenue at Allston Street, Allston||32 minutes||45 minutes||11 minutes|
|Warren Street||Commonwealth Avenue at Warren Street, Brighton||34 minutes||47 minutes||9 minutes|
|Summit Avenue||Commonwealth Avenue at Summit Avenue, Brighton||No longer a stop||Closed in 2005 to ease travel time.|
|Washington Street||Commonwealth Avenue at Washington Street, Brighton||36 minutes||49 minutes||7 minutes||65 Bus to Kenmore Square|
|Mount Hood Road||Commonwealth Avenue at Mount Hood Road, Brighton||No longer a stop||Closed in 2005 to ease travel time.|
|Sutherland Street||Commonwealth Avenue at Sutherland Road, Brighton||38 minutes||51 minutes||5 minutes|
|Chiswick Road||Commonwealth Avenue at Chiswick Road, Brighton||40 minutes||53 minutes||3 minutes|
|Chestnut Hill Avenue||Commonwealth Avenue at Chestnut Hill Avenue, Brighton||41 minutes||54 minutes||2 minutes||within easy walking distance of Cleveland Circle (C branch) and Reservoir (D branch)|
|South Street||Commonwealth Avenue at South Street, Brighton||42 minutes||55 minutes||1 minute|
|Greycliff Road||Commonwealth Avenue at Greycliff Road, Brighton||No longer a stop||Closed in 2005 to ease travel time.|
|Boston College||Commonwealth Avenue at Lake Street, Chestnut Hill, Boston serving Boston College||43 minutes||56 minutes||0 minutes||formerly Lake Street|
||This article has an unclear citation style. (September 2009)|
- Cleveland Circle History
- "Green Line B Branch Service Enhancements". TRANSreport. Boston Regional Metropolitan Planning Organization. May 2004. Retrieved 28 December 2012.
- T drops 4 Green Line stops after results of rider survey, The Boston Globe March 16, 2005
- Association for Public Transportation, Car-Free in Boston, A Guide for Locals and Visitors, 10th ed. (2003), p. 117.
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