Зелёная линия D: История и современность трамвайной ветки Риверсайд.

Light rail line

The Green Line D branch (also referred to as the Highland branch or Riverside Line) is a light rail line in Boston, Brookline, Cambridge, Newton, and Somerville, Massachusetts, operating as part of the Massachusetts Bay Transportation Authority (MBTA) Green Line. The line runs on a grade separated surface right of way for from Riverside station to Fenway station. The line merges into the C branch tunnel west of , then follows the Boylston Street subway and Tremont Street subway to It is the longest and busiest of the four Green Line branches. as of February 2023, service operates on 8 to 9 minute headways at weekday peak hours and 8 to 11 minute headways at other times, using 13 to 19 trains (26 to 38 light rail vehicles). Unlike the other three Green Line branches, the D branch did not originate as a streetcar line running on city streets. The Boston and Albany Railroad Highland branch, built in segments from 1848 to 1886, operated as a commuter rail line until its 1958 closure. It was converted to a streetcar rapid transit line by the Metropolitan Transportation Authority and reopened on July 4, 1959. Ownership passed to the MBTA in 1964; Tremont Street subway service was designated as the Green Line in 1965, with the Riverside Line becoming the D branch in 1967. The line was substantially rebuilt in the mid 1970s, in 2007, and in 2018–2020. The downtown terminal was shifted between , Government Center, North Station, and a number of times; it was extended to in September 2022 as part of the Green Line Extension project. Nine of the line's thirteen surface stations have been rebuilt for accessibility; the remaining four are scheduled for rebuilding beginning in 2024.

What is now the surface section of the D branch was formerly the Highland branch of the Boston and Albany Railroad (B&A). The portion between Brookline Junction and was built by B&A predecessor Boston and Worcester Railroad in 1848. The Charles River Branch Railroad extended the line to Newton Upper Falls in 1852, and later to Woonsocket, Rhode Island. Passenger service on the 1852 built line south of Cook Street ended in 1927. (A portion in Needham remains in use as part of the Needham Line).

Conversion of the Highland branch to a third rail rapid transit line was proposed in 1913. That proposal called for trains to reach downtown Boston using the then under construction Boylston Street subway, which was built for streetcars but sized for rapid transit conversion, with a connection near Governor Square. The plan, released in 1926, called for the existing streetcar subway to be converted into two rapid transit lines. A number of potential future extensions were listed; among them was conversion of most of the Highland branch to rapid transit, linking with a Huntington Avenue subway at Brookline Village. In 1943, the state legislature appointed a commission headed by Arthur W. Coolidge to plan for the future of transit in the Boston region. In 1945, a preliminary report from the Coolidge Commission recommended nine suburban rapid transit extensions – most similar to the 1926 plan – along existing railroad lines. The Highland branch was to be converted to a rapid transit line, using low floor trains that could operate in the existing streetcar subway. A branch would use the former Charles River Branch Railroad route to Separately, two tracks of the B&A mainline would be converted to rapid transit, also terminating at Riverside. The project was approved by the MTA Advisory Board on October 1, 1957, and the state Department of Public Utilities on December 6. The Interstate Commerce Commission gave a certificate of abandonment early in 1958. The B&A ran its last passenger trains on the branch on May 31, 1958. The MTA acquired the line from the B&A at a cost of $600,000 (equivalent to $0.6 in 1957 is equivalent to about <calculated amount> in recent years million in ) on June 24. Work began with a groundbreaking ceremony on July 10, 1958. Initial plans called for every other train to short turn at Reservoir. However, the outer section of the line had higher ridership than expected, and soon all trains operated to Riverside. From June 8 to September 11, 1974, buses ran between Kenmore and Reservoir while the inner portion of the line was reconstructed. A temporary loop was used near Reservoir station, allowing D branch trains to use the C branch between Reservoir and Kenmore. (On March 5, 1974, the downtown terminal had been cut back from Lechmere to North Station to accommodate the longer running times associated with this rerouting.) Weekend D branch service was extended to Lechmere on March 28, 1997; weekday service followed on June 21. It was cut back to Government Center on June 19, 2004, to accommodate the demolition of the Causeway Street elevated and the opening of the new underground North Station. Green Line service to Lechmere resumed on November 12, 2005, though the D branch continued to terminate at Government Center. The National Transportation Safety Board investigation concluded that the operator likely had an episode of micro sleep caused by sleep apnea. On October 25, 2010, the MBTA began operating some three car trains on the D branch at peak hours. This was expanded on March 21, 2011, but was discontinued on March 21, 2016, in favor of operating two car trains on more consistent headways. The Fenway Portal project was completed on November 23, 2020. The track and signal work was completed in December 2021. Three nine day closures of the whole D branch took place between September 24 and October 28, 2022, to allow for work including installation of a train protection system and track replacement between Eliot and Riverside.

Riverside station was rebuilt in the late 1990s, with raised platforms to provide accessible boarding on the then under construction Type 8 LRVs. Reservoir and Brookline Village were temporarily fitted with portable lifts for accessibility, with Brookline Hills added by 2003. Newton Centre, Reservoir, and Fenway were retrofitted with raised platforms around 2003. Woodland was rebuilt for accessibility in 2006, followed by Longwood and Brookline Village in 2009. Reconstruction of Brookline Hills station took place from September 2019 to January 2022 as part of the construction of an expansion of Brookline High School. Temporary work to make accessible was done in 2019–2020; a full reconstruction will begin in 2024. In 2019, the MBTA indicated that the remaining four non accessible stops (Beaconsfield, Chestnut Hill, Eliot, and Waban) were "Tier I" accessibility priorities. A preliminary design contract for accessibility modifications at the four stations was issued in February 2021. Design was completed in late 2022, with construction planned to begin in mid 2024.

Original plans for the Green Line Extension called for the D branch to be extended through the rebuilt Lechmere station to Medford/Tufts station, with several intermediate stops. However, in April 2021, the MBTA indicated that the D branch would instead be extended to , with the E branch running to Medford/Tufts. The D and E branches were chosen for the extension because they serve the Longwood Medical Area; the D branch was assigned to the shorter Union Square Branch because its western leg is longer than that of the E branch. The Union Square Branch opened on March 21, 2022. It was initially served by the E branch rather than the D branch. The western portion of the E branch was closed from August 6–20, 2022, for track work; during that time, Union Square was served by C branch trains plus Reservoir short turns from the D branch. Upon reopening, most D branch service (plus E branch service) began running to Union Square, though some peak hour trains short turned at Government Center. E branch trains began non revenue test service to Medford/Tufts on November 1, 2022, leaving only the D branch serving Union Square. The closure was originally planned for July 18 to August 28, but was delayed and shortened due to public criticism.

Location Station OpenedNotes and connectionsSomerville March 21, 2022 MBTA bus: East Cambridge MBTA bus: Original surface station was open from July 10, 1922, to May 23, 2020. West End August 20, 1955North End June 28, 2004 MBTA subway: MBTA Commuter Rail: Fitchburg, Lowell, Haverhill, Newburyport/Rockport MBTA bus: Amtrak: Original surface station was open from September 3, 1898 to March 27, 1997. Elevated station was open from June 1, 1912 to June 24, 2004. September 3, 1898 MBTA subway: MBTA bus: Downtown Boston MBTA subway: MBTA bus: September 1, 1897 MBTA subway: MBTA bus: At : ; MBTA subway: MBTA bus: Back Bay November 13, 1921 MBTA bus: October 3, 1914 MBTA bus: MBTA bus: Fenway–Kenmore October 23, 1932 MBTA bus: At : Framingham/Worcester July 4, 1959 MBTA bus: Brookline MBTA bus: MBTA bus: MBTA bus: At : (C)Newton MBTA bus: MBTA bus: 128 Business Council: MWRTA: MBTA bus: MWRTA: