Green Line A branch

A branch (Watertown Line)

Company type	Streetcar route
Industry	Public transportation
Founded	1858
Defunct	1969
Fate	Replaced by MBTA bus route 57
Headquarters	Boston, Massachusetts , United States
Area served	Boston metropolitan area
Products	Streetcar transit service

The A branch, also referred to as the Watertown Line, was a streetcar route serving the Boston, Massachusetts region, functioning as a branch of the Massachusetts Bay Transportation Authority Green Line. Its path extended from Watertown through Newton Corner, Brighton, and Allston to Kenmore Square, before continuing via the Boylston Street subway and Tremont Street subway to arrive at Park Street station.

Segments of this line originated as horsecar routes constructed between 1858 and 1880. The section connecting and was electrified in 1889, becoming part of the Beacon Street line. By 1896, electric streetcars operated from Newton Corner (Nonantum Square) to downtown Boston both through Brighton and via Watertown. Service from Brighton was extended to Watertown in 1912. The streetcar service continued until 1969, when it was supplanted by MBTA bus route 57; however, it remained in use for non-revenue transfers to Watertown Yard until 1994.

Origins

The Brighton Horse Railroad, a horse car street railway, began construction in 1858. This line started at Central Square, Cambridge, crossing the Charles River into Allston. It proceeded through Union Square along Cambridge Street and Washington Street to Oak Square in Brighton. Managed by the Union Street Railway under the Cambridge Railroad system, it commenced operations on November 15, 1858. Service frequency doubled in April 1878 with cars running every thirty minutes. A second Brighton–Cambridge line was launched in 1880 along Market Street and Western Avenue. Although an extension from Oak Square to Newton Corner was planned, it was never constructed; nevertheless, a line connecting Watertown and Nonantum Square existed.

During the late 1880s, the West End Street Railway acquired several horse railroads including the Cambridge Railroad. On January 3, 1889, West End inaugurated its inaugural electric streetcar route between Allston Carhouse and Park Square via Harvard Street and Beacon Street; electric service reached Oak Square on January 13. Electric streetcars began operating from Watertown to Mount Auburn on December 12, 1893 and the line was double-tracked within that decade. On August 18, 1896, the Western Avenue line was electrified and double-tracked—the final section over the West Boston Bridge to be converted; previously, horses pulled cars across the bridge before they were connected to electric cars from Allston into Boston.

Tracks extending eastward from Union Square along North Beacon Street and Commonwealth Avenue to Kenmore Square opened on May 18, 1896, joining with existing Beacon Street tracks. By June 13 of that year, the western terminus reached near Newton Corner (Nonantum Square). Starting November 8, 1897, Newton service via Commonwealth Avenue began utilizing the Tremont Street subway. A longer route from Nonantum Square to City Point passing through Allston and Coolidge Corner commenced operation on August 4, 1900. Service extended northward to Watertown along existing Galen Street tracks on December 9, 1912. Additionally, freight operations were conducted on this line during the early twentieth century.

The Boylston Street subway became operational up to Kenmore Square on October 3, 1914; immediately thereafter Watertown service via Brighton Center was routed through this tunnel. Mid-1915 saw the introduction of high-capacity center-entrance streetcars as trailers on the Watertown Line. On February 23, 1922 evening peak hour short-turn services at Oak Square were extended to Watertown. The Blandford Street portal opened on October 23, 1932 along Commonwealth Avenue west of Kenmore—this represented the final route modification. In 1941, PCC streetcars replaced older models on this line making it Boston’s first main route equipped with these vehicles.

North Beacon Street line

In June 1894, the West End sought municipal permission to establish a streetcar route along North Beacon Street, stretching from Union Square to the Watertown boundary. Shortly thereafter, the Newtonville and Watertown Street Railway obtained rights to construct tracks between and Union Square, planning to utilize West End rails to access downtown Boston. Although the Watertown Arsenal, which owned a portion of North Beacon Street, initially opposed the project, it granted approval in 1896 despite West End's objections. Construction of the line was completed in 1898.

After operational conflicts arose between its parent company, the Newton and Boston Street Railway, and the BERy, service commenced in 1900. On November 18 of that year, through service began linking Watertown with the Tremont Street subway as a branch of the Newton-Brighton line. In 1907, BERy acquired this route from Newton and Boston. A distinctive feature of this line was that the stretch west of Market Street remained single-tracked, unlike other BERy lines.

The Newton Street Railway, later renamed Middlesex and Boston Street Railway, introduced service between Waltham and Park Street via North Beacon Street on February 23, 1903. This route was altered in 1912 to run through Central Square via Arsenal Street and Western Avenue, while service between Oak Square and Boston was gradually shortened. Despite these changes, Watertown to Park Street service continued along North Beacon Street.

With the opening of the Boylston Street subway in October 1914, service on North Beacon Street was reduced to a shuttle running between Watertown and Union Square. By June 1917, this shuttle was further limited to operate only between the North Beacon Street bridge and Union Square, serving Brighton and Watertown.

On February 23, 1922, buses replaced this shuttle service. A short-lived bus route connecting Watertown to the Arsenal Street bridge operated during 1925–26. In December 1925, the Central Square–Union Square line was rerouted via Western Avenue and Soldiers Field Road. Subsequently, in September 1926, a new River Street bus route extended to Union Square took over streetcar operations. These two bus routes were merged by February 1933 to eliminate transfers; this combined service is currently known as the route 64 bus.

Closure

Prior to 1967, the Watertown Line was identified as route 69; meanwhile, what is now route 57 originally referred to short-turn trips on the Huntington Avenue line. The line carried the designation "A" as the northernmost branch of the Green Line. Turnback loops were located at Union Square, Oak Square, and at the Watertown terminus. Between 1915 and 1962, Braves Field featured a loop used for special event service along Commonwealth Avenue.

The inauguration of the Riverside Line in 1959 resulted in PCC streetcars being shifted from Cambridge routes to Riverside. However, by the late 1960s, an aging PCC fleet combined with maintenance challenges led to a shortage of Green Line streetcars. Consequently, the MBTA announced a "trial" discontinuation of the A branch. Factors influencing this decision included extensive street-running portions of the route and existing opposition to extending service beyond Newton Corner. Streetcar operations ended on June 20, 1969; bus service under route 57 commenced the next day.

Track removal

Following closure, tracks remained in place to facilitate streetcar access to Watertown Carhouse for maintenance purposes; their final use occurred in 1993 during refurbishment work on PCC streetcars serving the Ashmont–Mattapan High-Speed Line. Overhead electrical wires were dismantled in March 1994.

Most track infrastructure was removed by summer 1996 amid resurfacing work on North Beacon Street. Some remnants persist at Watertown Yard bus terminal and as a short track stub at Packard's Corner—previously used for storing disabled trains until its length was reduced in the mid-2000s; this switch was disconnected in 2014 and paved over by 2020.

Proposals to restore direct downtown streetcar service without requiring transfers at Kenmore were considered but ultimately rejected due to high costs and concerns over safety compared with existing bus alternatives.

Route 57

The 57 Watertown Yard–Kenmore station bus service was established in 1969, taking over from the A branch streetcar line. It largely follows the original path except at the Newton Corner rotary, where inbound buses travel in regular traffic lanes instead of a dedicated counterflow lane. Initially, the 57 operated as a limited-stop service between Packards Corner and Kenmore to supplement local service on the "B" branch; however, in December 2006, it expanded to make local stops along Commonwealth Avenue.

Prior to January 1, 2007, passengers boarding at Watertown had to pay double fares following the switch from streetcar to bus service due to the removal of free transfers. This policy was revised with the introduction of free transfers via the CharlieCard system.

Short-turn trips during peak periods between Oak Square and Kenmore were discontinued in 1971 but partially reinstated in 1987 and again in 1999. To alleviate crowding, the 57A Oak Square–Kenmore short-turn service was introduced on September 1, 2008. During rush hours, roughly half of the trips operated as 57A, while off-peak services ran the full route. Oak Square short-turn operations were eliminated in December 2020 except for a few school-day trips; at that time, full-route frequency was increased.

Route 57 remains a vital MBTA bus line, maintaining headways of approximately 10 to 12 minutes. When combined with the 57A service, it ranked as the ninth busiest route in 2012, with weekday boardings exceeding 10,000. Weekday operations are based out of Albany Street Bus Facility, while evening and weekend runs operate from Cabot Garage. An early morning trip to , internally designated as route 191 but publicly shown as a 57 trip, serves both MBTA personnel and general passengers.

A review conducted by the MBTA in 2018–19 highlighted issues with peak period overcrowding and reliability but did not recommend immediate changes. The comprehensive bus network redesign proposed in 2022 suggested increasing Route 57’s frequency to at least every 15 minutes throughout all operating hours. The 57A short-turn service was reinstated in December 2024 but discontinued again by April 2025.

Express buses

Two express routes serve downtown Boston via Copley Square west of Brighton Center:

• 501 Brighton Center–Federal Street & Franklin Street
• 504 Watertown Yard–Federal Street & Franklin Street

Express bus operations originating from Brighton and Watertown began in July 1967 with route 61, which underwent several renumberings (to 4, then 304) reflecting changes in express routing patterns. By June 1970, express routes were assigned numbers in the 300s series. Subsequent route modifications adjusted paths through Newton Corner, Oak Square, and Union Square. Service during midday and Saturdays expanded throughout the 1980s. In September 1996, routes were renumbered into the current 500-series format. Route 503 was introduced in January 2005 to connect Brighton Center with Copley Square.

A system review during 2018–19 identified challenges on routes 501 and 503 such as closely spaced stops and irregular afternoon scheduling; however, routes 502 and 504 did not present significant issues. To enhance operational efficiency starting September 2019, outbound buses on routes 502 and 504 were rerouted to bypass Newton Corner rotary, while routes 501 and 503 began serving Newton Corner stops outbound.

During the COVID-19 pandemic beginning March 2020, routes 502 and 503 were suspended; meanwhile, routes 501 and 504 operated on reduced schedules with route 504 using surface streets to reach Copley as a replacement for route 502. Route 501 was temporarily suspended from June through August of that year before resuming service to Copley Square. The network proposals issued in May 2022 made these pandemic-related adjustments permanent by restricting routes 501 and 504 to weekday peak periods only. Midday service on route 504 was restored in November 2022.

External links

• A visual comparison of Allston, showcasing historic streetcar photos alongside contemporary images of the same route hosted by Boston.com through the Wayback Machine