Long a hub of
streetcar development, San Francisco already had much of the overhead wire infrastructure necessary to deploy trolleybus service on existing city streets. A city ordinance requiring streetcars to use two operators also served to encourage trolleybus deployment. as some of the tracks would have to be taken up for the construction of the
Bay Bridge. By early August of that year, the
Market Street Railway Company (MSRy), successor to the URR, applied to the State Railroad Commission to operate the first trackless trolley system in California; permission was granted by August 30, and the first trolleybus service started on October 6, 1935, using 9 coaches built by Brill. The No. 33 Line had been originally established in 1892 by the San Francisco & San Mateo Railway Company as the 18th and Park or 18th Street Branch route. That route initially ran along 18th from Guerrero to Douglass before being extended to Frederick and Ashbury including a sharp
hairpin turn on the lower slopes of
Twin Peaks at Market and Clayton by May 1894. At the time of conversion, the No. 33 streetcar operated between Third & Harrison (
Downtown) and Waller & Stanyan (
Golden Gate Park), After riding the trackless trolley, the editor of the
San Bernardino Sun published a rumor that all streetcar service would eventually be replaced with trolleybuses. On September 7, 1941, Muni introduced its first trolleybus line to compete with MSRy, the
R-Howard line, using vehicles built by the St. Louis Car Company. The R-Howard line was introduced specifically so that Muni could undercut MSRy's prices on its parallel routes on
Mission Street. The routing for R-Howard followed a similar path from Howard & Beale along Howard and South Van Ness to South Van Ness & Army (now named Cesar Chavez). Although the overhead wires are still present along Howard, they are not used in revenue service. parallel to the original R-Howard route on Howard. By 1944, the MSRy was in financial difficulties. Thus, at 5 am on September 29, 1944, Muni acquired its commercial competitor. Along with the routes and equipment, Muni adopted its competitor's more expensive seven-cent fare ($ adjusted for inflation). In total,
fourteen streetcar lines were converted to trolleybus service by 1951. In 2019, the
California Air Resources Board set a mandate known as the
Innovative Clean Transit rule, which will require all public transit operators in the state to use zero-emissions buses, to eliminate
greenhouse gas emissions and combat
climate change. Analysis has found that maintenance and expansion of the trolleybus network in San Francisco could be the fastest and cheapest way for Muni to comply with the mandate and decarbonize its fleet.
Grade While many municipalities further converted their trolleybus systems to diesel buses during the middle of the 20th century, San Francisco maintained trolleybuses due to their ability to climb the city's notably steep
grades and because electricity was available at extremely low cost from the city-owned
O'Shaughnessy Dam. Muni has stated that it is impossible for some lines to be replaced by regular buses. The system includes the single steepest known grade on any existing trolleybus line in the world, specifically 22.8% in the block of Noe Street between Cesar Chavez Street and 26th Street on route
24 Divisadero, and several other sections of Muni trolleybus routes are among the world's steepest. 14TrSF trolleybus climbs
Nob Hill along Sacramento near Powell in 2007, a 17%
grade. On December 16, 1981, the 55-Sacramento line was converted from diesel motor coach service to trolleybus specifically to power the westward climb on Sacramento Street up
Nob Hill, and just six weeks later, on January 27, 1982, the
1 California route was revised to include the newly electrified sections of route 55, with the latter then discontinued. Before dieselization, the line on Sacramento had been operated using cable cars. At the time, Muni was also facing a severe shortage of available diesel motor coaches due to age and deferred maintenance, which would lead to the conversion of the 45-Greenwich diesel bus service to the 45-Union-Van Ness trolleybus in 1982 as a temporary experiment later made permanent. A year after being lengthened, route
24 Divisadero was converted to trolleybus operation in 1983. In 1993, the last major electric conversion took place when route
31 Balboa was partially converted to trolleybus service. Full implementation was delayed until 1994, when accessible Flyer E60 trolleybuses became available. Coming full circle, at the end of 1995 the 8-Market trolleybus line was replaced by the
F Market & Wharves streetcar line using refurbished PCCs. The overwhelming popularity of the new F line allowed Muni to reduce the frequency of and then discontinue the 8-Market, though the overhead wires remain in place. Approximately of the daily riders on Muni are carried on trolleybuses; in 2010, that was 227,000 passenger boardings per weekday. == Lines ==