Artificial leather called synthetic leather is a material intended to substitute for leather in upholstery, clothing and other uses where a leather-like finish is desired but the actual material is cost-prohibitive or unsuitable. Artificial leather is marketed under many names, including "leatherette", "faux leather", "vegan leather", "PU leather" and "pleather". Many different methods for the manufacture of imitation leathers have been developed. One of the earliest was Presstoff. Invented in 19th century Germany, it is treated paper pulp, it gained its widest use in Germany during the Second World War in place of leather, which under wartime conditions was rationed. Presstoff could be used in every application filled by leather, excepting items like footwear that were subjected to flex wear or moisture. Under these conditions Presstoff tends to lose cohesion. Poromerics are made from a plastic coating on a fibrous base layer; the term poromeric was coined by DuPont as a derivative of the terms polymeric.
The first poromeric material was DuPont's Corfam, introduced in 1963 at the Chicago Shoe Show. Corfam was the centerpiece of the DuPont pavilion at the 1964 New York World's Fair in New York City. After spending millions of dollars marketing the product to shoe manufacturers, DuPont withdrew Corfam from the market in 1971 and sold the rights to a company in Poland. Leatherette is made by covering a fabric base with a plastic; the fabric can be made of natural or synthetic fiber, covered with a soft polyvinyl chloride layer. Leatherette was common on the casings of 20th century cameras. Cork leather is a natural-fiber alternative made from the bark of cork oak trees, compressed, similar to Presstoff. A fermentation method of making collagen, the main chemical in real leather, is under development; the production of the PVC used in the production of many artificial leathers requires a plasticizer called a phthalate to make it flexible and soft. PVC requires petroleum and large amounts of energy thus making it reliant on fossil fuels.
During the production process carcinogenic byproducts, are produced which are toxic to humans and animals. Dioxins remain in the environment; when PVC ends up in a landfill it does not decompose like genuine leather and can release dangerous chemicals into the water and soil. Polyurethane is more popular for use than PVC. Artificial leathers are used in clothing fabrics, furniture upholstery, automotive uses. One disadvantage of plastic-coated artificial leather is that it is not porous and does not allow air to pass through. One of its primary advantages in cars, is that it requires little maintenance in comparison to leather, does not crack or fade easily. Clarino: manufactured by Kuraray Co. Ltd. of Japan. Fabrikoid: a DuPont brand, cotton cloth coated with nitrocellulose Lorica: manufactured by Lorica Sud, an Italian tannery MB-Tex: Used in many Mercedes-Benz base trims Naugahyde: An American brand introduced by Uniroyal Rexine: a British brand Kirza: A Russian form developed in the 1930s consisting of cotton fabric and rosin Piñatex: made from pineapple leaves Paguro: made from recycled rubber MuSkin: made from mushrooms that are treated non-chemically to become water resistant Kantala: Sri Lanken company specializing in leather made from the hana plant Bicast leather – a form of genuine leather coated with a plastic finish Bonded leather – a material made by blending scrap leather fibers with a plastic binder Microfiber – a material made with synthetic fibers thinner than natural silk.
Joseph Henry Press, 2007
Oakland is the largest city and the county seat of Alameda County, United States. A major West Coast port city, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third largest city overall in the San Francisco Bay Area, the eighth most populated city in California, the 45th largest city in the United States. With a population of 425,195 as of 2017, it serves as a trade center for the San Francisco Bay Area. An act to incorporate the city was passed on May 4, 1852, incorporation was approved on March 25, 1854, which made Oakland a city. Oakland is a charter city. Oakland's territory covers what was once a mosaic of California coastal terrace prairie, oak woodland, north coastal scrub, its land served as a rich resource when its hillside oak and redwood timber were logged to build San Francisco. Oakland's fertile flatland soils helped. In the late 1860s, Oakland was selected as the western terminal of the Transcontinental Railroad. Following the 1906 San Francisco earthquake, many San Francisco citizens moved to Oakland, enlarging the city's population, increasing its housing stock and improving its infrastructure.
It continued to grow in the 20th century with its busy port, a thriving automobile manufacturing industry. The earliest known inhabitants were the Huchiun Indians; the Huchiun belonged to a linguistic grouping called the Ohlone. In Oakland, they were concentrated around Lake Merritt and Temescal Creek, a stream that enters the San Francisco Bay at Emeryville. In 1772, the area that became Oakland was colonized, with the rest of California, by Spanish settlers for the King of Spain. In the early 19th century, the Spanish crown granted the East Bay area to Luis María Peralta for his Rancho San Antonio; the grant was confirmed by the successor Mexican republic upon its independence from Spain. Upon his death in 1842, Peralta divided his land among his four sons. Most of Oakland fell within the shares given to Antonio Vicente; the portion of the parcel, now Oakland was called Encinal—Spanish for "oak grove"—due to the large oak forest that covered the area, which led to the city's name. During the 1850s—just as gold was discovered in California—Oakland started growing and developing because land was becoming too expensive in San Francisco.
The Chinese were struggling financially, as a result of the First Opium War, the Second Opium War, the Taiping Rebellion, so they began migrating to Oakland in an effort to provide for their families in China. However, the Chinese struggled to settle because they were discriminated against by the white community and their living quarters were burned down on several occasions; the majority of the Chinese migrants lived in unhealthy conditions in China and they had diseases, so plague spread into San Francisco though the Chinese were inspected for diseases upon their arrival to San Francisco. In 1851, three men—Horace Carpentier, Edson Adams, Andrew Moon—began developing what is now downtown Oakland. In 1852, the Town of Oakland became incorporated by the state legislature. During this time, Oakland had 75-100 inhabitants, two hotels, a wharf, two warehouses, only cattle trails. Two years on March 25, 1854, Oakland re-incorporated as the City of Oakland, with Horace Carpentier elected the first mayor, though a scandal ended his mayorship in less than a year.
The city and its environs grew with the railroads, becoming a major rail terminal in the late 1860s and 1870s. In 1868, the Central Pacific constructed the Oakland Long Wharf at Oakland Point, the site of today's Port of Oakland. A number of horsecar and cable car lines were constructed in Oakland during the latter half of the 19th century; the first electric streetcar set out from Oakland to Berkeley in 1891, other lines were converted and added over the course of the 1890s. The various streetcar companies operating in Oakland were acquired by Francis "Borax" Smith and consolidated into what became known as the Key System, the predecessor of today's publicly owned AC Transit. Oakland was one of the worst affected cities in California, impacted by the plague epidemic. Quarantine measures were set in place at the Oakland ports requiring the authorities at the port to inspect the arriving vessels for the presence of infected rats. Quarantine authorities at these ports inspected over a thousand vessels per year for plague and yellow fever.
By 1908, over 5,000 people were detained in quarantine. Hunters were sent to poison the affected areas in Oakland and shoot the squirrels, but the eradication work was limited in its range because the State Board of Health and the United States Public Health Service were only allotted about $60,000 a year to eradicate the disease. During this period Oakland did not have sufficient health facilities, so some of the infected patients were treated at home; the State Board of Health along with Oakland advised physicians to promptly report any cases of infected patients. Yet, in 1919 it still resulted in a small epidemic of Pneumonic plague which killed a dozen people in Oakland; this started when a man killed a squirrel. After eating the squirrel, he fell ill four days and another household member contracted the plague; this in turn was passed on either indirectly to about a dozen others. The officials in Oakland acted by issuing death certificates to monitor the spread of plague. At the time of incorporation in 1852, Oaklan
Milk is a 2008 American biographical film based on the life of gay rights activist and politician Harvey Milk, the first gay person to be elected to public office in California, as a member of the San Francisco Board of Supervisors. Directed by Gus Van Sant and written by Dustin Lance Black, the film stars Sean Penn as Milk and Josh Brolin as Dan White, a city supervisor who assassinated Milk and Mayor George Moscone; the film earned numerous accolades from film critics and guilds. It received 8 Oscar nominations, including Best Picture, winning 2 for Best Actor for Penn and Best Original Screenplay for Black. Attempts to put Milk's life to film followed a 1984 documentary of his life and the aftermath of his assassination, titled The Times of Harvey Milk, loosely based upon Randy Shilts's biography, The Mayor of Castro Street. Various scripts were considered in the early 1990s, but projects fell through for different reasons, until 2007. Much of Milk was filmed on Castro Street and other locations in San Francisco, including Milk's former storefront, Castro Camera.
Milk begins on Harvey Milk's 40th birthday, when he was living in New York City and had not yet settled in San Francisco. It chronicles his foray into city politics, the various battles he waged in the Castro neighborhood as well as throughout the city, political campaigns to limit the rights of gay people in 1977 and 1978 run by Anita Bryant and John Briggs, his romantic and political relationships are addressed, as is his tenuous affiliation with troubled Supervisor Dan White. The film's release was tied to the 2008 California voter referendum on gay marriage, Proposition 8, when it made its premiere at the Castro Theatre two weeks before election day; the film opens with archival footage of police raiding gay bars and arresting patrons during the 1950s and 1960s, followed by Dianne Feinstein's November 27, 1978 announcement to the press that Harvey Milk and Mayor George Moscone had been assassinated. Milk is seen recording his will throughout nine days before the assassinations; the film flashes back to New York City in 1970, the eve of Milk's 40th birthday and his first meeting with his much younger lover, Scott Smith.
Dissatisfied with his life and in need of a change and Smith decide to move to San Francisco in the hope of finding larger acceptance of their relationship. They open Castro Camera in the heart of Eureka Valley, a working-class neighborhood in the process of evolving into a predominantly gay neighborhood known as The Castro. Frustrated by the opposition they encounter in the once Irish-Catholic neighborhood, Milk utilizes his background as a businessman to become a gay activist becoming a mentor for Cleve Jones. Early on, Smith serves as Milk's campaign manager, but he grows frustrated with Milk's devotion to politics, he leaves him. Milk meets Jack Lira, a sweet-natured but unbalanced young man; as with Smith, Lira cannot tolerate Milk's devotion to political activism, hangs himself. Milk clashes with the local gay "establishment" which he feels to be too cautious and risk-averse. After two unsuccessful political campaigns in 1973 and 1975 to become a city supervisor and a third in 1976 for the California State Assembly, Milk wins a seat on the San Francisco Board of Supervisors in 1977 for District 5.
His victory makes him the first gay man to be voted into major public office in California and the third homosexual politician in the entire US. Milk subsequently meets fellow Supervisor Dan White, a Vietnam veteran and former police officer and firefighter. White, politically and conservative, has a difficult relationship with Milk, develops a growing resentment for Milk when he opposes projects that White proposes. Milk and White forge a complex working relationship. Milk is invited to, attends, the christening of White's first child, White asks for Milk's assistance in preventing a psychiatric hospital from opening in White's district in exchange for White's support of Milk's citywide gay rights ordinance; when Milk fails to support White because of the negative effect it will have on troubled youth, White feels betrayed, becomes the sole vote against the gay rights ordinance. Milk launches an effort to defeat Proposition 6, an initiative on the California state ballot in November 1978. Sponsored by John Briggs, a conservative state legislator from Orange County, Proposition 6 seeks to ban gays and lesbians from working in California's public schools.
It is part of a nationwide conservative movement that starts with the successful campaign headed by Anita Bryant and her organization Save Our Children in Dade County, Florida to repeal a local gay rights ordinance. On November 7, 1978, after working tirelessly against Proposition 6, Milk and his supporters rejoice in the wake of its defeat. A desperate White favors a supervisor pay raise, but does not get much support, shortly after supporting the proposition, resigns from the Board, he changes his mind and asks to be reinstated. Mayor Moscone denies his request, after being lobbied by Milk. On the morning of November 27, 1978, White enters City Hall through a basement window to conceal a gun from metal detectors, he requests another meeting with Moscone, who rebuffs his request for appointment to his former seat. Enraged, White shoots Moscone in his office and goes to meet Milk, where he guns him down, with the fa
Mission San Francisco de Asís
Mission San Francisco de Asís, or Mission Dolores, is the oldest surviving structure in San Francisco and the sixth religious settlement established as part of the California chain of missions. The Mission was founded on October 9, 1776, by Lieutenant José Joaquin Moraga and Francisco Palóu, both members of the de Anza Expedition, charged with bringing Spanish settlers to Alta California and with evangelizing the local Natives, the Ohlone; some of the Mission's buildings have been turned into businesses, including a print shop and several saloons. The settlement was named for St. Francis of Assisi, the founder of the Franciscan Order, but was commonly known as "Mission Dolores" owing to the presence of a nearby creek named Arroyo de Nuestra Señora de los Dolores, meaning "Our Lady of Sorrows Creek." During the expedition of Juan Bautista de Anza, this site was identified by Pedro Font as the most suitable site for a mission in the San Francisco area. The original Mission was a small structure dedicated on October 9, 1776, after the required church documents arrived.
It was located near what is today the intersection of Camp and Albion Streets, about a block-and-a-half east of the surviving Adobe Mission building, on the shores of a lake called Laguna de Los Dolores. A historical marker at that location depicts this lake, but whether it actually existed is a matter of some dispute; the present Mission church, near what is now the intersection of Dolores and 16th Streets, was dedicated in 1791. At the time of dedication, a mural painted by native labor adorned the focal wall of the chapel; the Mission was constructed of adobe and was part of a complex of buildings used for housing and manufacturing enterprises. Though most of the Mission complex, including the quadrangle and Convento, has either been altered or demolished outright during the intervening years, the façade of the Mission chapel has remained unchanged since its construction in 1782–1791. According to Mission historian Brother Guire Cleary, the early 19th century saw the greatest period of activity at San Francisco de Asís: At its peak in 1810–1820, the average Indian population at Pueblo Dolores was about 1,100 people.
The California missions were not only houses of worship. They were farming communities, manufacturers of all sorts of products, ranches, hospitals and the centers of the largest communities in the state. In 1810 the Mission owned 11,000 sheep, 11,000 cows, thousands of horses, goats and mules, its ranching and farming operations east to Alameda. Horses were corralled on Potrero Hill, the milking sheds for the cows were located along Dolores Creek at what is today Mission High School. Twenty looms were kept in operation to process wool into cloth; the circumference of the Mission's holdings was said to have been about 125 miles. The Mission chapel, along with "Father Serra's Church" at Mission San Juan Capistrano, is one of only two surviving buildings where Junípero Serra is known to have officiated. In 1817, Mission San Rafael Arcángel was established as an Asistencia to act as a hospital for the Mission, though it would be granted full mission status in 1822; the Mexican War of Independence strained relations between the Mexican government and the California missions.
Supplies were scant, the Indians who worked at the missions continued to suffer terrible losses from disease and cultural disruption. In 1834, the Mexican government enacted secularization laws whereby most church properties were sold or granted to private owners. In practical terms, this meant that the missions would hold title only to the churches, the residences of the priests, a small amount of land surrounding the church for use as gardens. In the period that followed, Mission Dolores fell on hard times. By 1842, only eight Christian Indians were living at the Mission; the California Gold Rush brought renewed activity to the Mission Dolores area. In the 1850s, two plank roads were constructed from what is today downtown San Francisco to the Mission, the entire area became a popular resort and entertainment district; some of the Mission properties were leased for use as saloons and gambling halls. Racetracks were constructed, fights between bulls and bears were staged for crowds; the Mission complex underwent alterations.
Part of the Convento was converted to a two-story wooden wing for use as a seminary and priests' quarters, while another section became the "Mansion House," a popular tavern and way station for travelers. By 1876, the Mansion House portion of the Convento had been razed and replaced with a large Gothic Revival brick church, designed to serve the growing population of immigrants who were now making the Mission area their home. During this period, wood clapboard siding was applied to the original adobe chapel walls as both a cosmetic and a protective measure. During the 1906 San Francisco earthquake, the adjacent brick church was destroyed. By contrast, the original adobe Mission, though damaged, remained in good condition. However, the ensuing fire touched off by the earthquake reached to the Mission's doorstep
Sandra Dee was an American actress. Dee began her career as a child model, working in commercials before transitioning to film in her teenage years. Best known for her portrayal of ingénues, Dee earned a Golden Globe Award as one of the year's most promising newcomers for her performance in Robert Wise's Until They Sail, she became a teenage star for her subsequent performances in Imitation of Life and Gidget, which made her a household name. By the late 1960s, her career had started to decline, a publicized marriage to Bobby Darin ended in divorce, she acted after this time, her final years were marred by illness. She died in 2005 at age 62 of complications from kidney disease, brought on by a lifelong struggle with anorexia nervosa. Dee was born Alexandra Zuck on April 23, 1942 in Bayonne, New Jersey, the only child of John Zuck and Mary Zuck, who met as teenagers at a Russian Orthodox church dance, they divorced before Sandra was five years old. She was of Carpatho-Rusyn ancestry, raised in the Russian Orthodox faith.
Her son, Dodd Darin, wrote in his biographical book about his parents, Dream Lovers, that Dee's mother and her aunt Olga "were first generation daughters of a working-class Russian Orthodox couple." Dee recalled, "we belonged to a Russian Orthodox Church, there was dancing at the social events." Alexandra would soon take the name Sandra Dee. She became a professional model by the age of 4 and subsequently progressed to television commercials. There has been some dispute as to Dee's actual birth year, with evidence pointing to both 1942 and 1944. Legal records, including her California divorce record from Bobby Darin, as well as the Social Security Death Index and her own gravestone all give her year of birth as 1942. In a 1967 interview with the Oxnard Press-Courier, she acknowledged being 18 in 1960 when she first met Bobby Darin, the couple wed three months later. According to her son's book, Dee was born in 1944, having begun modelling and acting at a young age and her mother falsely inflated her age by two years so she could find more work.
Dee's parents divorced in 1950, her mother married a man, sexually abusing Sandra and continued to do so after he married her mother. Producer Ross Hunter claimed to have discovered Dee on Park Avenue in New York City with her mother when she was twelve years old. In a 1959 interview, Dee recalled that she "grew up fast", surrounded by older people, was "never held back in anything wanted to do". During her modeling career, Dee attempted to lose weight to "be as skinny as the high-fashion models", although an improper diet "ruined skin, nails—everything". Having slimmed down, her body was unable to digest any food she ate, it took the help of a doctor to regain her health. According to the actress, she "could have killed " and "had to learn to eat all over again". In spite of the damaging effects on her health, Dee earned a generous $75,000 in 1956 working as a 12 or 14-year-old model in New York, which she used to support herself and her mother after the death of her stepfather. According to sources, Dee's large modeling salary was more than she would come to earn as an actress.
Ending her modeling career, Dee moved from New York to Hollywood in 1957. After studying at the Hollywood Professional School, she graduated from University High School in Los Angeles in June 1958. Dee's onscreen debut was in the 1957 Metro-Goldwyn-Mayer film Until They Sail, directed by Robert Wise. To promote the film, Dee appeared in a December issue of Modern Screen in a column by Louella Parsons, who praised the young girl and compared her looks and talent to those of Shirley Temple, her performance made her one of that year’s winners of the Golden Globe Award for New Star of the Year – Actress. MGM cast her as the female lead in The Reluctant Debutante, with John Saxon as her romantic co-star was, the first of several films they made together, she provided the voice for The Snow Queen. Despite or because of her newfound success, the effects of sexual abuse, Dee continued to struggle with anorexia nervosa, which led to her kidneys temporarily shutting down. In 1958, Dee was signed with Universal Pictures, was one of the company's last contract players prior to the dissolution of the old studio system She had a lead role in The Restless Years for producer Ross Hunter, opposite Saxon and Teresa Wright.
She followed this with another for A Stranger in My Arms. Her third film for Hunter had the biggest impact: Imitation of Life, opposite Lana Turner; the film became a wild box office success. At the time, it was Universal Pictures's highest-grossing film in history, making Dee a household name. Columbia Pictures borrowed her to play the titular role in the teenage beach comedy Gidget, a solid hit, helping spawn the beach party genre and leading to two sequels, two television series and two television movies. For a complete change of pace, Universal cast her opposite Audie Murphy in a Western romantic comedy, The Wild and the Innocent, playing a tomboy, it was not popular. Warner Bros. borrowed her for another melodrama in the vein of Imitation of Life, A Summer Place, opposite Troy Donahue as her romantic co-star. The film was a massive hit, that year US box office exhibitors voted her the 16th most popular star in the country. Hunter reunited her with Lana Turner and John Saxon in Universal's Portrait in Black, a reasonably popular thriller.
Dee was the nation's seventh biggest star at the end of 1960. Peter Ust
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
The Muni Metro is a light rail system serving San Francisco, operated by the San Francisco Municipal Railway, a division of the San Francisco Municipal Transportation Agency. With an average weekday ridership of 162,500 passengers as of the fourth quarter of 2017, Muni Metro is the United States' third busiest light rail system. Muni Metro operates a fleet of 151 Breda light rail vehicles, which are being supplemented and replaced by Siemens S200 SF LRVs. Muni Metro is the modern incarnation of the traditional streetcar system that had served San Francisco since the late 19th century. While many streetcar lines in other cities, in San Francisco itself, were converted to buses after World War II, five lines survived until the early 1980s, when they were rerouted into the newly built Market Street Subway; the system today traverses a number of different types of rights of way, including tunnels, reserved surface trackage with at-grade street crossings, streetcar sections operating in mixed traffic.
The system has undergone expansion, most notably the Third Street Light Rail Project, completed in 2007, which started the first new rail line in San Francisco in over half a century. Other projects, such as the Central Subway, are underway; the first street railroad in San Francisco was the San Francisco Market Street Railroad Company, incorporated in 1857 and began operating in 1860, with track along Market Street from California to Mission Dolores. Muni Metro descended from the municipally-owned traditional streetcar system started on December 28, 1912, when the San Francisco Municipal Railway was established; the first streetcar line, the A Geary, ran from Kearny and Market Streets in the Financial District to Fulton Street and 10th Avenue in the Richmond District. The system expanded, opening the Twin Peaks Tunnel in 1917, allowing streetcars to run to the southwestern quadrant of the city. By 1921, the city was operating 25 miles of cable car lines; the last line to start service before 2007 was the N Judah, which started service after the Sunset Tunnel opened in 1928.
In the 1940s and 1950s, as in many North American cities, public transit in San Francisco was consolidated under the aegis of a single municipal corporation, which began phasing out much of the streetcar network in favor of buses. However, five used streetcar lines traveled for at least part of their routes through tunnels or otherwise reserved right-of-way, thus could not be converted to bus lines; as a result, these lines, running PCC streetcars, continued in operation. Original plans for the BART system drawn up in the 1950s envisioned a double-decked subway tunnel under Market Street in downtown San Francisco. However, by 1961 these plans were altered; the new tunnel would be connected to the existing Twin Peaks Tunnel. The new underground stations would feature high platforms, the older stations would be retrofitted with the same, which meant that the PCCs could not be used in them. Hence, a fleet of new light rail vehicles was ordered from Boeing-Vertol, but were not delivered until 1979–80 though the tunnel was completed in 1978.
The K and M lines were extended to Balboa Park during this time, providing further connections to BART. On February 18, 1980, the Muni Metro was inaugurated, with weekday N line service in the subway; the Metro service was implemented in phases, the subway was served only on weekdays until 1982. The K Ingleside line began using the Metro subway on weekdays on June 11, 1980, the L Taraval and M Ocean View lines on December 17, 1980, lastly the J Church line on June 17, 1981. Meanwhile, weekend service on all five lines continued to use PCC cars operating on the surface of Market Street through to the Transbay Terminal, the Muni Metro was closed on weekends. At the end of the service day September 19, 1982, streetcar operations on the surface of Market Street were discontinued the remaining PCC cars taken out of service, weekend service on the five light rail lines was temporarily converted to buses. On November 20, 1982, the Muni Metro subway began operating seven days a week. At the time, there were no firm plans to revive any service on the surface of Market Street or return PCCs to regular running.
However, tracks were rehabilitated for the 1983 Historic Trolley Festival and the inauguration of the F Line, served by heritage streetcars, followed in 1995. By the late 1980s, Muni scheduled 20 trains per hour through the Market Street Subway at peak periods, with all trains using the crossover west of Embarcadero station to reverse direction.. To allow for high frequencies on the surface branches, eastbound trains were combined at West Portal and Duboce Portal, westbound trains split at those locations. Two-car N Judah trains and one-car J Church trains combined at the Duboce Portal, while two-car L Taraval trains alternately combined with two-car M Ocean View and K Ingleside trains at West Portal to form four-car trains. However, this provided suboptimal service. In the mid- to late-1990s, San Francisco grew m