The N Judah is a Muni Metro light rail line in San Francisco, California, so named as it runs along Judah Street for much of its length, named after railroad engineer Theodore Judah. It links downtown San Francisco to the Cole Sunset neighborhoods, it is the busiest line in the Muni Metro system, serving an average of 41,439 weekday passengers in 2013. It was one of San Francisco's streetcar lines, beginning operation in 1928, was converted to modern light-rail operation with the opening of the Muni Metro system in 1980. While many streetcar lines were converted to bus lines after World War II, the N Judah remained a streetcar line due to its use of the Sunset Tunnel; the line runs from the Caltrain depot in the Mission Bay district to Ocean Beach and the Great Highway in the Sunset District. From the Caltrain depot at Fourth and King Streets, it runs along King Street and the Embarcadero, passing by Oracle Park, it enters the Market Street Subway, which it shares with the five other Muni Metro lines.
It exits the tunnel at Church Street and, after a brief stretch along Duboce Avenue to Duboce Park, enters the older Sunset Tunnel. This tunnel contains no underground stations. From the western end of the tunnel, the route goes along Carl Street, past UCSF-Parnassus Campus, on Irving Street, until it turns onto 9th Avenue for one block and reaches Judah Street, which the N runs on for the rest of its route. On Judah between 9th Avenue and 19th Avenue the N runs on a right-of-way, raised above the surrounding street. There is a loop in the intersection at Judah, La Playa and Great Highway that the N uses to turn around; the N Judah line stops at large stations for the downtown section of the route and at smaller stops on the rest of the line. Most of the smaller stops consist of nothing more than a sign on the side of a street designating a stop, while other stops are concrete "islands" in the middle of a street next to the tracks that provide access for wheelchairs. Muni bus routes provide service to all downtown stations and other systems with access to the stations are noted.
As with all Muni lines, service begins around 5 a.m. on weekdays, 6 a.m. on Saturdays, 8 a.m. on Sundays and holidays. It operates at high frequencies between 7 and 12 minutes, utilizes two-car trains during Muni Metro hours of operation. Late night service is provided by the N Owl diesel bus line; this line is the same as the daytime N Judah line, except it follows surface streets instead of going through the streetcar-only Market Street Subway and Sunset Tunnel. At the Ferry Portal at The Embarcadero and Folsom, it stays on The Embarcadero to Mission/Don Chee Way takes Steuart for one block and turns onto Market Street, which it follows past all five underground stations served by the daytime N Judah line, it takes Church and Fillmore to get to Haight Street, where it bypasses the steep hill above the Sunset Tunnel, serves the Lower Haight and Haight-Ashbury neighborhoods. It turns off Haight at Cole, rejoins the daytime N line at Carl. On January 10, 1998, Muni opened the Muni Metro Extension to King/Caltrain.
It was served by a temporary shuttle service, the E Embarcadero, which ran between Embarcadero station and 4th and King/Caltrain. On August 22, 1998, the E Embarcadero line was eliminated and the N Judah line was extended in its place. A variety of service changes took place with the introduction of full service on the T Third Street line on April 7, 2007; the N Judah was cut back to Embarcadero station. The changes were unpopular with the public. On June 30, 2007, Muni reversed several of the changes. On December 5, 2009, the N Judah was cut to Embarcadero on weekends as part of widespread service reductions. Weekend service was re-extended on October 15, 2011. After concerns from riders of constant overcrowding of the trains on the N Judah line, Muni debuted an express bus route called the NX Judah Express on June 13, 2011. Starting off as a pilot program, the NX was intended to relieve overcrowding during rush hours every ten minutes, it follows the western end of the N Judah route from Ocean Beach to 19th Avenue operates nonstop from there to the Financial District where it stops at Bush and Montgomery Streets.
In September 2016, Muni began running a pair of one-car shuttles between Embarcadero station and Carl and Hillway during morning rush hour to reduce crowding on the inner section of the line. A study after one month showed the shuttles had increased capacity on the inner part of the line by 18% and reduced the number of passengers unable to board overcrowded trains by 63%. In March 2018, the SFMTA board voted to shorten rush-hour headways from 7 minutes to 4 minutes, but to only use one-car trains on weekends; the changes will take effect in the summer. Future plans, according to the SFMTA Rail Capacity Strategy, include a new subway tunnel which connects to the Market Street Subway to 9th Avenue. Additionally, the N Judah line will be rebuilt to run three car trains. Further plans include a non-revenue L Taraval to N Judah connector. N Judah on SFMTA's site N Judah schedule "N Judah map". Archived from the original on 2015-10-09. N Judah route information from the SF Muni Map Project The N-Judah Chronicles
Powell Street station
Powell Street is a shared Muni Metro and Bay Area Rapid Transit station near the intersection of Market Street and Powell Street in downtown San Francisco. The station is located along the Market Street Subway and extends underground from Fourth Street to Fifth Street. Hallidie Plaza connects to the station on the north side of Market Street. Like all of the shared BART and Muni stations on the Market Street Subway, the concourse mezzanine is on the first level down, an island platform for the Muni Metro is on the second level down, the island platform for BART is on the third level down; the Powell-Mason and Powell-Hyde cable car lines turn around at Powell and Market, above the station. BART service at Powell Street station began on November 5, 1973, followed by Muni service on February 18, 1980; as of October 2017, Powell Street was the busiest station on weekends in the BART system. Like the three other shared BART/Muni stations in the Market Street Subway, Powell station has three levels: a fare mezzanine on the first level, an island platform for Muni Metro on the second level, an island platform for BART on the third level.
As with the other three stations, Powell station was built with several entrances on each side of Market Street leading to the fare concourse. There is a direct entrance to the fare concourse from the basement level of the Westfield San Francisco Centre mall. A closed passageway leads from the northeast end of the station under Market Street partway to Third Street; the fare concourse has two BART fare payment areas and two Muni Metro fare payment areas. The Powell-Mason and Powell-Hyde cable car lines turn around at Powell and Market, above the station, the F Market and Wharves streetcar line and a number of bus routes operate on the surface; the under-construction Central Subway, expected to open in 2019, passes under the Powell station complex. The new Union Square/Market Street station will be located north of Powell station under Stockton Street; the stations will be connected outside of fare control by a passageway. The Stockton/Ellis entrance to the station was closed for a planned five years on April 24, 2013, so that it could be modified to include the connection to the new station.
The closure was planned for the previous August, but delayed after Muni determined it was not yet needed. Muni purchased the entrance from BART for one dollar. Following the 2015 addition of a canopy over an escalator at 19th Street Oakland station, which reduced escalator downtime by one-third, BART decided to add canopies to all downtown Oakland and San Francisco entrances; the canopies will protect the escalator from weather damage, improve lighting, allow the escalator to be closed off when the station is not open, provide a location for real-time train arrival information displays. The Powell station entrance at Market and Ellis was chosen for early implementation; the remaining Powell station entrances will have similar canopies added beginning in 2019, with completion in 2025. In September 2015, BART released a report on possible modernization of the station. A total of $93 million in potential improvements were identified, including escalator replacement and canopy construction, a corridor to Cyril Magnin, a new mid-station elevator, platform screen doors, additional platform stairs, numerous other projects.
Pigeons living in the station are a nuisance, which has prompted BART to take countermeasures like installing nets and metal screens to block their nesting spots. The pigeons are attracted by nearby street food vendors. Two Muni heritage streetcar stops are located above Powell Street station: Market and 4th Street / Market and Stockton, Market and 5th Street. Both are served by the F Market and Wharves line; the Powell and Market turntable of the San Francisco cable car system, terminus of the Powell/Hyde and Powell/Mason lines, is located adjacent to the station next to Haladie Plaza. The station is served by a number of Muni bus and trolleybus routes: Local: 5, 6, 7, 8, 9, 21, 27, 30, 31, 45 Rapid: 5R, 9R Express: 7X, 8AX, 8BX, 81X Owl service: 91 Owl, L Owl, N OwlAC Transit serves Powell Street station with the 800 All Nighter route during hours that BART is not operating; the station is served by Amtrak buses connecting to trains at Emeryville station. Additional Muni, Golden Gate Transit, SamTrans bus routes run on Mission Street, one block away.
Under the planned Better Market Street project, F stops would be consolidated to reduce travel times. The inbound stop at 5th Street and both stops at 4th Street would be discontinued, with a new inbound stop midway between 4th and 5th. List of Bay Area Rapid Transit stations Media related to Powell Street station at Wikimedia Commons BART - Powell Street
San Francisco Municipal Railway
The San Francisco Municipal Railway is the public transit system for the city and county of San Francisco, California. In 2006, Muni served 46.7 square miles with an operating budget of about $700 million. In ridership terms, Muni is the seventh largest transit system in the United States, with 210,848,310 rides in 2006 and the second largest in California behind Metro in Los Angeles. With a fleet average speed of 8.1 mph, it is the slowest major urban transit system in America and one of the most expensive to operate, costing $19.21 per mile per bus and $24.37 per mile per train. However, it has more boardings per mile and more vehicles in operation than similar transit agencies. Muni is an integral part of public transit in the city of San Francisco, operating 365 days a year and connecting with regional transportation services, such as Bay Area Rapid Transit, SamTrans, Golden Gate Transit, AC Transit, its network consists of 54 bus lines, 17 trolley bus lines, 7 light rail lines that operate above ground and in the city's lone subway tube, 3 cable car lines, 2 heritage streetcar lines, the E Embarcadero and F Market.
Many weekday riders are commuters, as the daytime weekday population in San Francisco exceeds its normal residential population. Muni shares four metro stations with BART. Most bus lines are scheduled to operate every five to fifteen minutes during peak hours, every five to twenty minutes middays, about every ten to twenty minutes from 9 pm to midnight, every half-hour for the late night "owl" routes. On weekends, most Muni bus lines are scheduled to run every ten to twenty minutes. However, complaints of unreliability on less-often-served lines and older trolleybus lines, are a system-wide problem. Muni has had some difficulty meeting a stated goal of 85% voter-demanded on-time service. All Muni lines run inside San Francisco city limits, with the exception of several lines serving locations in the northern part of neighboring Daly City, the 76X Marin Headlands Express line to the Marin Headlands area on weekends and major holidays. Most intercity connections are provided by BART and Caltrain heavy rail, AC Transit buses at the Transbay Terminal, Golden Gate Transit and SamTrans downtown.
Bus and car stops throughout the city vary from Metro stations with raised platforms in the subway and at the more used surface stops, to small shelters to signposts to a yellow stripe on a utility pole or on the road surface. 70% of stops are spaced closer than recommended range of 800–1,000 feet apart. Muni is not an acronym; the Muni metro is called "the train" or "the streetcar." Most San Francisco natives use'Muni'. The E Embarcadero and F Market & Wharves lines are referred to by Muni as a "historic streetcar line" rather than as a "heritage railway."Muni's logo is a stylized, trademarked "worm" version of the word muni. This logo was designed by San Francisco-based graphic designer Walter Landor in the mid-1970s. Bus and trolleybus lines have number designations, rail lines have letters and the three cable car lines are referred to by name only. Except for cable cars, cash fares are $2.75 for adults. Clipper card and MuniMobile fares are $2.50 for adults and $1.25 for seniors and people with disabilities.
Proof-of-payment, which fare inspectors may demand at any time, is either a Clipper card, Muni Passport, or paper transfer. One fare entitles a rider to unlimited vehicle transfers for the next 120 minutes. Cable cars are $7 one way, with no transfers unless the rider has Fast Pass; as of July 2017 monthly passes cost $75 for adults, $38 for low-income residents, or $38 for youth and the disabled. Passes are valid on all Muni lines—including cable cars—and the $94 adult Fast Pass allows BART transit within San Francisco. Other passes and stickers are valid on all Muni lines, including cable cars, but not on BART. Cable car fare is $7 per trip, with no transfers accepted. "Passports" are folding scratch-off passes that can be purchased by mail, or at various places throughout the city. Muni has implemented a dual-mode smart card payment system known as Clipper; the transponders have been in use since at least 2004, replaced most paper monthly passes in 2010. BART, Golden Gate Transit, VTA, AC Transit, SamTrans, SMART and San Francisco Bay Ferry utilize the Clipper system.
Muni operates 14 express lines, 5 Rapid lines, 12 Owl lines, which run between 1 am and 5 am. For San Francisco Giants games, additional "baseball shuttles" supplement N Judah and T Third service to AT&T Park. Express lines only run during peak hours. All express lines "BX" following the line's number; some lines are divided into B Expresses. The B Express line is shorter and has sto
Market Street (San Francisco)
Market Street is a major thoroughfare in San Francisco, California. It begins at The Embarcadero in front of the Ferry Building at the northeastern edge of the city and runs southwest through downtown, passing the Civic Center and the Castro District, to the intersection with Corbett Avenue in the Twin Peaks neighborhood. Beyond this point, the roadway continues as Portola Drive into the southwestern quadrant of San Francisco. Portola Drive extends south to the intersection of St. Francis Boulevard and Sloat Boulevard, where it continues as Junipero Serra Boulevard. Market Street is the boundary of two street grids. Streets on its southeast side are parallel or perpendicular to Market Street, while those on the northwest are nine degrees off from the cardinal directions. Market Street is a major transit artery for the city of San Francisco, has carried in turn horse-drawn streetcars, cable cars, electric streetcars, electric trolleybuses, diesel buses. Today Muni's buses and heritage streetcars share the street, while below the street the two-level Market Street Subway carries Muni Metro and Bay Area Rapid Transit.
While cable cars no longer operate on Market Street, the surviving cable car lines terminate directly adjacent to the street at its intersections with California Street and Powell Street. Market Street cuts across the city for three miles from the waterfront to the hills of Twin Peaks, it was laid out by Jasper O'Farrell, a 26-year-old trained civil engineer who emigrated to Yerba Buena. The town was renamed San Francisco in 1847 after it was captured by United States troops during the Mexican–American War. O'Farrell first repaired the original layout of the settlement around Portsmouth Square and established Market Street as the widest street in town: 120 feet between property lines, it was described at the time as an arrow aimed straight at "Los Pechos de la Chola", now called Twin Peaks. Writing in Forgotten Pioneers, T. F. Pendergast wrote: When the engineer had completed his map of Market Street and the southern part of the city, what was regarded as the abnormal width of the proposed street excited part of the populace, an indignation meeting was held to protest against the plan as wanton disregard for rights of landowners.
A friend warned O'Farrell. He rode with all haste to North Beach, took a boat for Sausalito, thence put distance behind him on fast horses in relay until he reached his retreat in Sonoma, he found. At the time, the Market Street right-of-way was blocked by a sixty-foot sand dune where the Palace Hotel is now located, a hundred yards further west stood a second sandhill nearly ninety feet tall; the city soon filled in the ground between Portsmouth Square and Happy Valley at First and Mission Street. The dunes were leveled and the sand used for fill; the first horsecar-powered railway line to open in San Francisco commenced running down the thoroughfare on July 4, 1860, operating under the Market Street Railroad Company. By 1918 Muni was in direct competition with the United Railroads of San Francisco down the length of Market Street; the two Union Railroad tracks were on the inside and the two San Francisco Municipal Railway tracks were on the outside. In 1892 The Owl Drug Company was established at 1128 Market Street and grew into a leading American drugstore retailer.
Willis Polk designed the Path of Gold Street Lamps in 1908 for United Railways’ trolley poles with street lights. The tops were designed in 1916 by engineer Walter D'Arcy Ryan; the Winning of the West bases were designed by sculptor Arthur Putnam and feature three historical subjects: covered wagons, mountain lions, alternating prospectors and Indians. The City required the ornamental poles to permit the much-opposed overhead trolley wires. Market Street underwent major changes in the late 1960s and early 1970s, when Muni Metro service was moved underground in concert with the development of the Bay Area Rapid Transit system. Construction of the Market Street Subway commenced in July 1967. Prolonged disruption to what had traditionally been the social and economic center of the city contributed to the decline of the mid-Market shopping district in years. In 1980, Muni's surface operations were routed underground with full service changes occurring in 1982. While there were no plans to retain the surface tracks, several Historic Trolley Festivals had proven popular enough to reinstate operations in the form of the F Market historic streetcar line.
Market Street parades have long marked global events, such as the Panama-Pacific International Exposition, the Preparedness Day bombing of 1916, the parade of the influenza-masked revelers of the first Armistice Day, the 1934 general strike that paralyzed the ports of the Pacific Coast, the end of World War II. In the days of the first United Nations conferences, Anthony Eden, Molotov and Bidault rode up Market Street, waving to the crowds of hopefuls. On Christmas Eve 1910, opera singer Luisa Tetrazzini sang a free outdoor concert to a crowd some estimated at 250,000, following a dispute with Oscar Hammerstein. Another historic Market Street event was the New Year's Eve celebration at the Ferry Building on December 31, 1999. Over 1.2 million people jammed Market Street and nearby
The volt is the derived unit for electric potential, electric potential difference, electromotive force. It is named after the Italian physicist Alessandro Volta. One volt is defined as the difference in electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points, it is equal to the potential difference between two parallel, infinite planes spaced 1 meter apart that create an electric field of 1 newton per coulomb. Additionally, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it, it can be expressed in terms of SI base units as V = potential energy charge = J C = kg ⋅ m 2 A ⋅ s 3. It can be expressed as amperes times ohms, watts per ampere, or joules per coulomb, equivalent to electronvolts per elementary charge: V = A ⋅ Ω = W A = J C = eV e; the "conventional" volt, V90, defined in 1987 by the 18th General Conference on Weights and Measures and in use from 1990, is implemented using the Josephson effect for exact frequency-to-voltage conversion, combined with the caesium frequency standard.
For the Josephson constant, KJ = 2e/h, the "conventional" value KJ-90 is used: K J-90 = 0.4835979 GHz μ V. This standard is realized using a series-connected array of several thousand or tens of thousands of junctions, excited by microwave signals between 10 and 80 GHz. Empirically, several experiments have shown that the method is independent of device design, measurement setup, etc. and no correction terms are required in a practical implementation. In the water-flow analogy, sometimes used to explain electric circuits by comparing them with water-filled pipes, voltage is likened to difference in water pressure. Current is proportional to the amount of water flowing at that pressure. A resistor would be a reduced diameter somewhere in the piping and a capacitor/inductor could be likened to a "U" shaped pipe where a higher water level on one side could store energy temporarily; the relationship between voltage and current is defined by Ohm's law. Ohm's Law is analogous to the Hagen–Poiseuille equation, as both are linear models relating flux and potential in their respective systems.
The voltage produced by each electrochemical cell in a battery is determined by the chemistry of that cell. See Galvanic cell § Cell voltage. Cells can be combined in series for multiples of that voltage, or additional circuitry added to adjust the voltage to a different level. Mechanical generators can be constructed to any voltage in a range of feasibility. Nominal voltages of familiar sources: Nerve cell resting potential: ~75 mV Single-cell, rechargeable NiMH or NiCd battery: 1.2 V Single-cell, non-rechargeable: alkaline battery: 1.5 V. Some antique vehicles use 6.3 volts. Electric vehicle battery: 400 V when charged Household mains electricity AC: 100 V in Japan 120 V in North America, 230 V in Europe, Asia and Australia Rapid transit third rail: 600–750 V High-speed train overhead power lines: 25 kV at 50 Hz, but see the List of railway electrification systems and 25 kV at 60 Hz for exceptions. High-voltage electric power transmission lines: 110 kV and up Lightning: Varies often around 100 MV.
In 1800, as the result of a professional disagreement over the galvanic response advocated by Luigi Galvani, Alessandro Volta developed the so-called voltaic pile, a forerunner of the battery, which produced a steady electric current. Volta had determined that the most effective pair of dissimilar metals to produce electricity was zinc and silver. In 1861, Latimer Clark and Sir Charles Bright coined the name "volt" for the unit of resistance. By 1873, the British Association for the Advancement of Science had defined the volt and farad. In 1881, the International Electrical Congress, now the International Electrotechnical Commission, approved the volt as the unit for electromotive force, they made the volt equal to 108 cgs units of voltage
T Third Street
The T Third Street is a Muni Metro line in San Francisco, California. It is the first new light rail line in San Francisco in more than half a century, the first accessible line in the system, it is the first true light rail line in the streetcar Muni Metro system, as it operates in a street median, rather than in mixed traffic. Testing on the line took place in summer 2006, with limited service starting on January 13, 2007, full service beginning on April 7, 2007, it runs along the newly constructed light-rail tracks on Third Street and Bayshore Boulevard in the Visitacion Valley, Bayview/Hunters Point and Mission Bay neighborhoods, connecting to the existing Muni Metro system along the southern Embarcadero and below Market Street, replaced the 15 Third bus line. In the future, the line may be extended to Caltrain's Bayshore Station and, in the other direction, to San Francisco's Washington Square in North Beach via Chinatown Central Subway alignment. Following service changes on June 30, 2007, the T Third Street and the K Ingleside lines were spliced together in the Market Street Subway tunnel, resulting in a route from Balboa Park, through downtown, to Bayshore and Sunnydale.
At West Portal Station, inbound K trains heading through downtown to Third Street change their signs to the T line. Each train displays its ultimate destination; this system will continue in place. Leaving the Market Street Subway at Ferry Portal heading south, the T Third follows The Embarcadero south of Market Street veers onto King Street in front of Oracle Park until it reaches the Caltrain station terminal; this portion of the Muni Metro rail line between the Embarcadero portal and the Caltrain terminal was built in 1998 and is utilized by an extension of the N Judah, which shares track with the T to the Caltrain terminal at 4th and King. From there the T turns south on Fourth Street, crossing the bridge over Mission Creek before joining Third Street for the majority of the route's length, it passes through Mission Bay where the UCSF Mission Bay branch is located continues on south through the Bayview and Hunters Point neighborhoods. Once both economically impoverished parts of the City, they have experienced rehabilitation and rebuilding helped by the new T line.
At the intersection of Third and Jamestown Avenue, the T continues to run in both directions as it crosses U. S. Highway 101, although only Third Street is open to auto traffic northbound. From there the T follows Bayshore Boulevard for two more stations until it reaches its terminus at Sunnydale Station. A section of track follows one more block. All stations along this line feature high platforms, eliminating the need for the raising and lowering of entrance and exit steps characteristic of other Muni Metro lines. Stations south of Fourth and King feature short platforms; the T Third uses the Muni Metro terminology in which an inbound train goes from West Portal to Embarcadero. This means that an outbound T Third train runs from Sunnydale and out to the western neighborhoods via downtown; this is the reverse of other lines, as those lines have their outer termini on the southwest and west sides of the city, those trains enter the subway from the west going inbound toward downtown. The underground section of the line was closed west of Castro station from June 25 to August 24, 2018 due to the Twin Peaks Tunnel shutdown.
On August 25, 2018, at the conclusion of the shutdown, Muni began running permanently two-car trains on the K/T line. The line was shut down from January 22, 2019 until April 1, 2019 for construction of a new platform at UCSF/Mission Bay station. T-Third has been built in phases; the first phase extended rail service south to Sunnydale Station. The second phase under construction, is known as the Central Subway project, will reroute T-Third north of the 4th and King Station; the future alignment once the second phase is complete will neither share right-of-way with, nor share identities with the K Ingleside, avoiding both King Street and the congested Market Street subway. The southern segment from Sunnydale to 4th and King Street will remain as-is, operating on street-level tracks in the median of Third Street and Bayshore Boulevard. After 4th and King, the line will cross King Street instead of turning onto it, proceed to a new 4th and Brannan Station, the line will burrow to subsurface level at Bryant Street Portal, near where 4th passes under Interstate 80.
Underground, the line will continue under Fourth Street, to Yerba Buena/Moscone Station, after crossing Market Street, will turn to continue under Stockton Street, continuing to Union Square/Market Station providing a transfer to Market Street Subway MUNI and BART lines before running underneath Stockton Street and terminating at Chinatown Station. To complement the Central Subway, Muni is constructing the Mission Bay Loop, an additional loop along the T Third line that would enable more frequent short-line service to the section of the line from Mission Bay through the Central Subway. MBL would connect the existing T Third tracks on 3rd Street to additional tracks along 18th Street, Illinois Street, 19th Street to connect back to 3rd Street. A proposed third phase would build an extension beyond Chinatown, in
Twin Peaks (San Francisco)
The Twin Peaks are two prominent hills with an elevation of about 925 feet located near the geographic center of San Francisco, California. Only 928 foot; the North and South Twin Peaks known as "Eureka" and "Noe" are about 660 ft apart. The peaks form a divide for the summer coastal fog pushed in from the Pacific Ocean, their west-facing slopes get fog and strong winds, while the east-facing slopes receive more sun and warmth. Elevation at each summit is just over 900 feet. Thin, sandy soil is commonplace on Twin Peaks. Before the arrival of the Europeans, the native Ohlone people may have used Twin Peaks as a lookout or hunting ground; the ecological diversity of Twin Peaks provided medicinal or ceremonial plants and berries. When the Spanish conquistadors and settlers arrived at the beginning of the 18th century, they called the area "Los Pechos de la Chola" or "Breasts of the Indian Maiden" and devoted the area to ranching; when San Francisco passed under American control during the 19th century, it was renamed "Twin Peaks".
Christmas Tree Point lies some 70 ft below the North Peak and offers vistas of San Francisco and San Francisco Bay. The view to the north extends no farther than Cobb Mountain 120 km away, but looking southeast down the Santa Clara Valley on a clear day, Santa Ana Mountain 36.8782°N 121.2637°W / 36.8782. To the north is one of the city's many reservoirs, it is owned by the San Francisco Fire Department, supplies water to the Fire Department's independent HPFS water system for fighting fires, established after the 1906 earthquake and fire. The top of Twin Peaks is undeveloped, it is part of the 31 acres Twin Peaks Natural Area and owned by the San Francisco Recreation and Parks Department. These preserved areas are home to wildlife; as part of the Mission blue butterfly habitat conservation, Twin Peaks is one of the few remaining habitats for this endangered species. Many bird species and vegetation thrive in these areas; the Muni Metro Twin Peaks Tunnel runs beneath Twin Peaks, linking Downtown San Francisco with West Portal and the southwestern part of the city.
There is no public transportation all the way to the top of the Peaks, but the 37 Corbett Muni line stops on Crestline Drive near a path up the hill. The San Francisco Police Department Academy is at the base of the peaks; the name "Twin Peaks" is applied to the surrounding neighborhood. The San Francisco Unified School District operates the Ruth Asawa San Francisco School of the Arts in the Twin Peaks neighborhood. 49-Mile Scenic Drive List of San Francisco, California Hills Coffey, Geoffrey. "Treasures in the curves and swells of Twin Peaks". San Francisco Chronicle