Trolleybuses in Greater Boston

A Flyer trolleybus in the upper level of the Harvard bus tunnel in 2003

What became the Harvard-based trolleybus system began as branches of the Cambridge Railroad, a horsecar street railway that opened in 1856. Lines from Harvard Square to Mount Auburn via Brattle Street and Porter Square opened soon after the Harvard Square–Bowdoin Square route.[5][6] The connecting Watertown Horse Railroad opened on April 27, 1857.[7] The Porter Square branch was extended to the border of West Cambridge (now Arlington); there it met the West Cambridge Horse Railroad, which opened on June 13, 1859.[6][8] In 1880, the Watertown line was extended south on Galen Street to Nonantum Square.[9]

The Harvard–Arlington line was electrified on July 1, 1889 – one of the first lines converted by the West End Street Railway.[10] Electric service between Watertown and Mount Auburn began on December 12, 1893; the line was double-tracked later in the decade.[11][12] Residents of Brattle Street objected to the construction of electric lines; in October 1893, the Board of Railway Commissioners denied the West End permission to run electric streetcars on Brattle Street.[5][13][14] That November, a compromise was worked out where the West End would instead build on Mount Auburn Street (which had been considered in 1891[15]); the line on Concord Avenue and Huron Avenue would be opened within eight months, and the Brattle Street horsecar tracks removed in the same time frame.[16] The Mount Auburn line opened in April or May 1894, with the Concord/Huron line opening later in the year.[17][18][19]

A branch from Mount Auburn to Waverley Square in Belmont opened on October 1, 1898, despite Watertown's opposition earlier than year to widening Belmont Street.[20][21] A branch to Belmont Center opened on June 30, 1906; it was replaced by buses in August 1928 and was never a trackless trolley route.[22][23][24]

The four surviving Harvard-based routes remained after much of the system was converted to diesel and exist, in part, because of the necessity to limit the number of diesel buses in the Harvard bus tunnel. Inside the portals, the tunnel splits into two one-way tunnels, upper and lower. The tunnel for eastbound-northbound vehicles is placed on top of the tunnel for southbound-westbound vehicles.[25] The tunnels first opened for streetcars in 1912, and trolleybuses began using them in 1938.[4] Streetcar service using the tunnel was abandoned in 1958. In a six-year project lasting from 1979 to 1985 (coinciding with the reconstruction of Harvard station during the Northwest Extension of the MBTA Red Line), the tunnel was closed for an extensive rebuilding, which included new platforms and a new northern portal ramp.[4]

1976 Flyer E800 trolleybus at Cambridge Common, followed by the newer Neoplan AN-440LF trolleybus

In the lower/westbound tunnel, the loading platforms are located on the left side of the roadway, and for this reason the trolleybuses serving this station have always been equipped with left-side doors, in addition to the normal righthand doors, as state DPU regulations discourage boarding passengers from doors facing the wall rather than the platform. Diesel buses serving the tunnel are not equipped with left-side doors, and passengers boarding or deboarding at the westbound stop must cross the roadway to reach the buses' doors.[25] In 2004, the MBTA began receiving a fleet of new trolleybuses from Neoplan USA, to replace Flyer E800 trolleybuses dating from 1976. The newer vehicles are low-floor vehicles and meet Americans with Disabilities Act standards (see MBTA accessibility).

The vehicles are all stored overnight at the North Cambridge Carhouse, the northern terminus of the 77A route. Trackless trolleys do not run on Sundays; instead, diesel buses cover the routes.

To expedite passenger boarding through a left-side door in the southbound Harvard bus tunnel, the 71 and 73 trackless trolley routes allow free entry for outbound trips, collecting fare upon later passenger exit from the vehicle. Diesel buses lack a left-side door, so on Sundays these buses are boarded in the northbound tunnel.

The #71 route terminates at Watertown Square

The 71 Watertown Square–Harvard station begins at the Harvard bus tunnel lower level and leaves via the south exit onto Mount Auburn Street. It heads west into Watertown, ending at Watertown Square.

At the Harvard end, to turn around, the trackless trolley exits the tunnel and makes a hard left onto Massachusetts Avenue and a right on Garden Street, and then turns right on Waterhouse Street and right on Massachusetts Avenue to return to the tunnel. The Watertown end has a loop on private right-of-way for turning around and picking up/dropping off passengers.

September 4, 1958, was the last day of streetcar service on the 71; trackless trolleys have run since then. On December 22, 2019, additional reverse-peak short turns were added. These trips serve Mount Auburn Hospital and return trolleybuses to the route 72 terminals for its peak-direction-only service.[26]

The 72 Aberdeen Avenue–Harvard station starts on the upper level and comes out the north end of the tunnel, using the path that the 71 uses to turn around. However, at the intersection of Garden and Waterhouse Streets, the 72 heads west on Garden Street, Concord Avenue and Huron Avenue and south on Aberdeen Avenue to end at Mount Auburn Street, intersecting the 71 and 73.

To turn around, the 72 leaves the south portal of the tunnel and turns left on Mount Auburn Street. It turns right on Eliot Street, right on Bennett Street and right on a private right-of-way called Bennett Alley to go straight across Mount Auburn Street into the tunnel. At the west end, the 72 simply makes a U-turn across the wide median of Aberdeen Avenue. On Saturday evenings and Sundays, the 72 is combined with the 75 bus and the route extends to Belmont Center as a diesel bus (signed as route 72/75).

Streetcars last ran on the 72 on April 1, 1938; trackless trolleys have been running since then. In March 2013, the route was temporarily replaced with diesel buses to permit roadwork on Huron Avenue and reconstruction of the Conductor's Building in Bennett Alley.[27] It will return to electric operation when construction is complete. However, route 72 was reduced to peak-direction, peak-hour-only service on December 22, 2019 in conjunction with improvements to routes 74 and 75 (which also run on Concord Avenue).[28]

The 73 Waverley Square–Harvard station follows the same route as the 71 in Cambridge. It leaves Mt. Auburn St. to follow Belmont Street, which forms a border between Belmont and Watertown, then continues on Trapelo Road in Belmont to end at Waverley Square, with a loop at the Waverley commuter rail station on the Fitchburg Line. A short-turn loop exists at Benton Square, the intersection of Belmont Street and Trapelo Road.

September 4, 1958, was the last day of streetcar service on the 73 (and 71 and 77A), after which trackless trolleys have run. As a streetcar line, the turnback loop was further west along Trapelo Road at Cushing Square. Streetcars first ran to Waverley Square on October 1, 1898.

In September 2013, the route was converted to diesel buses for two years to permit diversions during roadway reconstruction in Belmont. Trackless trolley service was restored in December 2016. A small number of Benton Square short turns (added to the schedule in March 2016) continue to operate as diesel buses.[27]

The 77A is a short-turn trip of the 77 Arlington Heights–Harvard station bus route. It is not a full-service route; it is primarily a designation for route 71 and 73 trolleybuses to run in revenue service while pulling in or out of the North Cambridge Carhouse. The route was originally a full-service short turn route; however, it became less necessary after the Red Line was extended to Porter and Davis stations in 1984. Since January 2005, the only 77A trips are pull-ins and pull-outs to take 71 and 73 buses to or from the carhouse.[27] They are listed in the 77 schedule.

September 4, 1958, was the last day of streetcar service on the 77A, after which trackless trolleys have run. (Route 77 had already been running diesel buses since 1955.) Until around 1967, the route was numbered 82.

Boston's first trolleybuses were built by Pullman-Standard in 1936. Boston Elevated continued to buy its trolleybuses almost exclusively from Pullman, and until 1950 Pullmans comprised the entire fleet with the exception of a small batch of five Twin Coach trolleybuses purchased in 1937.[2][29] In 1952, Boston had more Pullman-built trolleybuses than any other city, with 438.[29]^:7 Meanwhile, 25 ACF-Brill trolleybuses built in 1950 were the only other purchase of non-Pullman trolleybuses until 1976. With several route closures in 1964, the Twin Coaches and the oldest Pullmans were retired, leaving only Pullmans built in 1947–51 in service. These were all replaced in 1976 by a fleet of 50 Flyer E800s.[25] The Flyers were, in turn, replaced by new trolleybuses over the period 2004–06.

The present fleet is made up of low-floor vehicles built by Neoplan USA and fitted with Škoda electrical equipment. There are two distinct groups: The network serving Cambridge and vicinity uses a fleet of 28 40-foot (12 m) vehicles, while the Silver Line (Waterfront) uses a fleet of 32 60-foot (18 m) articulated dual-mode buses which are extended-length.

The Cambridge trolleybuses (numbered 4101–4128) were delivered in 2004 and were the first low-floor trolleybuses in North America.[30] The first day of service for trolleybuses in this series was June 4, 2004.[31] The dual-mode, articulated vehicles (numbered 1101–1132) were delivered in 2004–2005 and are also low-floor vehicles.