Sound of San Francisco Muni Metro departing train / Siemens S200 SF

Muni Metro is a hybrid light rail/streetcar system serving San Francisco, California, United States, operated by the San Francisco Municipal Railway (Muni), a division of the San Francisco Municipal Transportation Agency (SFMTA). With a daily average weekday ridership of 157,700 passengers (as of 2019), Muni Metro is the United States' second-busiest light rail system. Muni Metro operates a fleet of 151 Breda high-floor light rail vehicles (LRVs), which are currently being replaced by a fleet of 249 Siemens S200 LRVs. Muni Metro is considered to be one of the surviving first-generation streetcar systems in North America, with some lines serving San Francisco since the late 19th century. While many streetcar lines in other cities, and even in San Francisco itself, were converted to buses after World War II, five lines survived because they used dedicated rights-of-way or used narrow tunnels that could not be used by buses. Those remaining lines were rerouted into the newly built Market Street subway in the early 1980s. Today, the system traverses a number of different types of rights of way, including tunnels, exclusive surface routes with at-grade street crossings, and streetcar sections operating in mixed traffic. Because Muni Metro is one of the surviving first-generation systems, it differs in operation from most of the second-generation light rail systems built since the 1980s. Most lines operate like a modern light rail line on a portion of their route, making stops at stations, and as a streetcar making stops in the middle of a street (like a bus) on the other part. The exceptions are the S Shuttle line, and the newest line, T Third Street which operate as a modern light rail line over their entire route. Because the system uses high-floor vehicles, while operating as a streetcar, the vehicles are not accessible to people with disabilities that impact their mobility. A select number of stops, typically located near major intersections, are equipped with ramps or lifts, for people with disabilities. The Siemens S200 is a high-floor light rail vehicle (LRV) manufactured by Siemens Mobility in Florin, California. The S200 model succeeds the SD-100, SD-160, SD-400 and SD-460 as the high-floor version of Siemens's light rail vehicle for North America, and is being manufactured and marketed with the low-floor S700.