Green Line (MBTA)

Green Line
Green Line train at Park Street station in 2024
Overview
Owner	Massachusetts Bay Transportation Authority
Locale	Boston, Brookline, Cambridge, Medford, Newton, and Somerville, Massachusetts
Termini	North/east terminals: Union Square (D) Medford/​Tufts (E) Government Center (B and C) South/west terminals: Boston College (B) Cleveland Circle (C) Riverside (D) Heath Street (E)
Stations	70
Service
Type	Semi-metro, Light rail
System	MBTA subway
Services	4 (B branch, C branch, D branch, E branch)
Rolling stock	Kinki Sharyo Type 7 AnsaldoBreda Type 8 CAF Type 9
Daily ridership	101,000 (2023)[1]
History
Opened	September 1, 1897 (1897-09-01) (Tremont Street subway)
Technical
Line length	26.7 miles (43.0 km) [2]
Character	Subway, grade-separated surface ROW, viaduct, median reservation, street running
Track gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Minimum radius	33 feet (10 m)[3]
Electrification	Overhead line, 600 V DC
Route map Show interactive map Legend Mystic Valley Parkway proposed Medford/​Tufts Green Line Extension Ball Square Magoun Square Gilman Square East Somerville Green Line Extension Union Square Lechmere Lechmere ( closed 2020 ) Lechmere Viaduct over Charles River Science Park Causeway Street Elevated ( closed 2004 )  Orange Line  North Station Canal Street Incline ( closed 2004 ) Haymarket  Orange Line  Government Center Park Street Tremont Street subway Boylston Boylston Street subway Arlington Copley Copley Junction E branch E branch Prudential Symphony Northeastern University Museum of Fine Arts Longwood Medical Area Brigham Circle Fenwood Road Mission Park Riverway Back of the Hill Heath Street Arborway Line ( closed 1985 ) Arborway Line ( closed 1985 ) Forest Hills  Orange Line  Arborway Hynes Convention Center Kenmore B branch B branch Blandford Street Portal Blandford Street Boston University East Boston University Central Amory Street Babcock Street A branch ( closed 1969 ) A branch ( closed 1969 ) Packards Corner St. Luke's Street Chester Street Linden Street Harvard Avenue Allston Street Union Square Cambridge Street street-running stops Washington Street street-running stops Oak Square Oak Square Loop Washington Street street-running stops Newton Corner Galen Street street-running stops Watertown Yard Packards Corner Harvard Avenue Griggs Street Allston Street Warren Street Washington Street Sutherland Road Chiswick Road Chestnut Hill Avenue to Reservoir Carhouse South Street Boston College C branch C branch Saint Mary's Street Portal Saint Mary's Street Hawes Street Kent Street Saint Paul Street Coolidge Corner Summit Avenue Brandon Hall Fairbanks Street Washington Square Tappan Street Dean Road Englewood Avenue D branch D branch Fenway Portal Fenway Longwood Brookline Village Brookline Hills Beaconsfield Cleveland Circle Reservoir Carhouse Cleveland Circle to B branch Reservoir D branch D branch Chestnut Hill Newton Centre Newton Highlands Eliot Waban Woodland Riverside Riverside Riverside Carhouse  Framingham/Worcester Line  This diagram: view talk edit Show route diagram map

The Green Line is a semi-metro system^[4][5] (form of light rail) run by the Massachusetts Bay Transportation Authority (MBTA) in the Boston, Massachusetts, metropolitan area. It is the oldest MBTA subway line, and with tunnel sections dating from 1897, the oldest subway in North America.^[6] It runs underground through downtown Boston, and on the surface into inner suburbs via six branches on radial boulevards and grade-separated alignments. With an average daily weekday ridership of 101,000 in 2023, it is among the most heavily used light rail systems in the country. The line was assigned the green color in 1967 during a systemwide rebranding because several branches pass through sections of the Emerald Necklace of Boston.^[7][8][9]

The four branches are the remnants of a large streetcar system, which began in 1856 with the Cambridge Horse Railroad and was consolidated into the Boston Elevated Railway several decades later. The branches all travel downtown through the Tremont Street subway, the oldest subway tunnel in North America. The Tremont Street subway opened its first section on September 1, 1897, to take streetcars off overcrowded downtown streets; it was extended five times over the next five decades. The streetcar system peaked in size around 1930 and was gradually replaced with trackless trolleys and buses, with cuts as late as 1985. The new D branch opened on a converted commuter rail line in 1959. The Green Line Extension project extended two branches into Somerville and Medford in 2022.