1928. Muni began operating buses in 1917, and trolleybuses in 1941. The city acquired the competing Market Street Railway in 1944, doubling the size of Muni; its purchase of the bankrupt California Street Cable Railroad in 1952 made it the city's sole transit operator. Replacement of streetcars by buses in the 1940s and 1950s left only five streetcar lines; they were converted to Muni Metro light rail in 1980 with the completion of the Market Street subway. Numerous service changes over the lifetime of Muni gave rise to the lines in use today; a number of other lines have been discontinued. During the COVID-19 pandemic, service was initially reduced to a limited set of "core service" routes, then gradually expanded. , six Muni Metro routes, one streetcar route, one bus replacement for a Muni Metro route, three cable car routes, 43 local bus routes, four Rapid routes, and three express routes are in operation. Several of those routes have been temporarily modified. Twelve overnight Owl routes and one early-morning express route are in operation. Cable car lines All three cable car lines are based out of the cable car barn at Mason and Washington. Muni Metro and historic streetcar lines Muni runs six Muni Metro light rail lines (J, K, L, M, N, and T), plus a shuttle service (S). The S Shuttle operates as an additional subway service at peak hours; extended S service is also used to serve events at Oracle Park (primarily San Francisco Giants games) and Chase Center (primarily Golden State Warriors games). Two streetcar lines (E and F) use historic streetcars but serve as full transit routes rather than mere tourist attractions. Muni Metro lines are based out of two yards, Green Division (located at Balboa Park station) and Muni Metro East; the historic streetcar lines are based at Cameron Beach Yard (also near Balboa Park). All routes except the E Embarcadero and L Taraval are in operation; bus replacements operate for the L Taraval. Local bus lines Muni operates 44 local bus routes. Most routes operate on weekdays and weekends; the 41 and 88 operate only during weekday peak hours. A number of routes have different terminals during evenings and/or weekends. Route 2, which uses diesel hybrid buses, is supplemented by short turn trolleybuses at peak hours. Route 5 uses trolleybuses only during evenings and weekends. Rapid bus lines On five high-ridership corridors, local