The New York City Subway is a rapid transit system that serves four of the five boroughs of New York City, New York: the Bronx, Brooklyn, Manhattan, and Queens. Its operator is the New York City Transit Authority (NYCTA), which is controlled by the Metropolitan Transportation Authority (MTA) of New York. In 2016, an average of 5.66 million passengers used the system daily, making it the busiest rapid transit system in the United States and the seventh busiest in the world.

By the late 1870s the Manhattan Railway Company was an elevated railway company in Manhattan and the Bronx, New York City, United States. It operated four lines: the Second Avenue Line, Third Avenue Line, Sixth Avenue Line, and Ninth Avenue Line. The first underground line opened on October 27, 1904, almost 35 years after the opening of the first elevated line in New York City, which became the IRT Ninth Avenue Line. By the time the first subway opened, the lines had been consolidated into two privately owned systems, the Brooklyn Rapid Transit Company (BRT, later Brooklyn–Manhattan Transit Corporation, BMT) and the Interborough Rapid Transit Company (IRT). After 1913, all lines built for the IRT and most lines for the BRT were built by the city and leased to the companies. The first line of the city-owned and operated Independent Subway System (IND) opened in 1932, intended to compete with the private systems and replace some of the elevated railways. It was required to be run "at cost", necessitating fares up to double the five-cent fare popular at the time.

The city took over running the previously privately operated systems in 1940, with the BMT on June 1 and the IRT on June 12. Some elevated lines closed immediately while others closed soon after. Integration was slow, but several connections were built between the IND and BMT, which now operate as one division called the B Division. Since IRT infrastructure is too small for B Division cars, it remains as the A Division.

The NYCTA, a public authority presided over by New York City, was created in 1953 to take over subway, bus, and streetcar operations from the city. In 1968 the state-level MTA took control of the NYCTA, and in 1970 the city entered the New York City fiscal crisis. It closed many elevated subway lines that became too expensive to maintain. Graffiti, crime, and decrepitude became common. To stay solvent, the New York City Subway had to make many service cutbacks and defer necessary maintenance projects. In the 1980s an $18 billion financing program for the rehabilitation of the subway began.

The September 11 attacks resulted in service disruptions, particularly on the IRT Broadway–Seventh Avenue Line, which ran directly underneath the World Trade Center. Sections were crushed, requiring suspension of service on that line south of Chambers Street. By March 2002, seven of the closed stations had been rebuilt and reopened, and all but one on September 15, 2002, with full service along the line.Brian Abbott. September 11: Three Years Later. Several maps showing changes in lower Manhattan from July 2001 to September 2002.

Since the 2000s, expansions include the 7 Subway Extension that opened in September 2015, and the Second Avenue Subway, the first phase of which opened on January 1, 2017.MTA.info—Second Avenue Subway Quarterly Report Q4 2013The Launch Box—Fewer Than 1,000 Days to Go! However, at the same time, under-investment in the subway system led to a transit crisis that peaked in 2017.

Precursors

Steam railways

Even though there was an earlier, underground railroad called the Atlantic Avenue Tunnel since 1844, it had no underground subway stops.Citynoise: Oldest Subway Tunnel in the World . Retrieved April 8, 2009. Construction of this tunnel, which was built mainly to create a grade-separated right of way for the Brooklyn and Jamaica Railroad (now the Long Island Rail Road's Atlantic Branch), began in May 1844, and the tunnel was open by December 1844. This led to South Ferry at the foot of Atlantic Avenue, where passengers could catch ferries to Manhattan. This extension, running under Cobble Hill, was closed by 1861. The tunnel was reopened for tourism in 1982,Multiple sources:

and closed again in 2010.

The beginnings of the actual Subway came from various excursion railroads to Coney Island and elevated railroads in Manhattan and Brooklyn. At that time, New York County (Manhattan Island and part of the Bronx), Kings County (including the cities of Brooklyn and Williamsburg), and Queens County were separate municipal entities. Competing steam-powered elevated railroads were built over major avenues. The first elevated line was constructed from 1867 to 1870 by Charles Harvey and his West Side and Yonkers Patent Railway company along Greenwich Street and Ninth Avenue (although cable cars were the initial mode of transportation on that railway). More lines were built on Second, Third and Sixth Avenues. None of these structures remain today, but these lines later shared trackage with subway trains as part of the IRT system.

In Kings County, elevated railroads were built by several companies over Lexington, Myrtle, Third and Fifth Avenues, Fulton Street and Broadway. These also later shared trackage with subway trains operated by the BRT and BMT. Most of these structures have been dismantled, but some have been rebuilt and upgraded. These lines were linked to Manhattan by various ferries and later the tracks along the Brooklyn Bridge (which originally had their own line and were later integrated into the BRT/BMT). Also in Kings County, six steam excursion railroads were built to various beaches in the southern part of the county; all but one (the Manhattan Beach Line) eventually fell under BMT control.

Beach Pneumatic Transit

The Beach Pneumatic Transit was the first attempt to build an underground public transit system in New York City. In 1869, Alfred Ely Beach and his Beach Pneumatic Transit Company of New York began constructing a pneumatic subway line beneath Broadway. Funneled through a company he set up, Beach put up $350,000 of his own money to bankroll the project."Inventor of the Week – Alfred Beach" (MIT) Built in only 58 days, its single tunnel, long, in diameter, was completed in 1870 and ran under Broadway from Warren Street to Murray Street.

It remained little more than a curiosity, running only a single car on its one-block-long track to a dead-end at its terminus. Passengers would simply ride out and back, to see what the proposed subway might be like. During its first two weeks of operation, the Beach Pneumatic Transit sold over 11,000 rides, with 400,000 rides provided during its first year of operation."The Secret Subway" (PBS) Although the public showed initial approval, Beach was delayed in getting permission to expand it. By the time he finally gained permission in 1873, public and financial support had waned, and the subway was closed down.

The final blow to the project was a stock market crash in 1873 which caused investors to withdraw support."Beach Pneumatic Transit – The Interborough Rapid Transit subway" (plrog.org) After the project was shut down, the tunnel entrance was sealed, and the station, built in part of the basement of the Rogers Peet Building, was reclaimed for other uses. The entire building was lost to fire in 1898. In 1912, workers excavating for the present-day BMT Broadway Line dug into the old Beach tunnel; today, no part of this line remains as the tunnel was completely within the limits of the present day City Hall Station under Broadway.nycsubway.org—Beach Pneumatic Transit

Beginnings and rapid expansion

The first subways

IRT

In 1898, New York, Kings and Richmond Counties, and parts of Queens and Westchester Counties and their constituent cities, towns, villages, and hamlets, were consolidated into the City of Greater New York. During this era the expanded City of New York resolved that it wanted the core of future rapid transit to be underground subways but realized that no private company was willing to put up the enormous capital required to build beneath the streets.

Planning for the system began with the Rapid Transit Act, authorized by the New York State Legislature on May 22, 1894, which created the Board of Rapid Transit Railroad Commissioners. The act provided that the commission would lay out routes with the consent of property owners and local authorities, either build the system or sell a franchise for its construction, and lease the operation to a private firm. A line through Lafayette Street (then Elm Street) to Union Square was considered, but at first a more costly route under lower Broadway was adopted. A legal battle with property owners along the route led to the courts denying permission to build through Broadway in 1896.James Blaine Walker, Fifty Years of Rapid Transit, 1864–1917, published 1918, pp. 139–161

The Elm Street route was chosen later that year, cutting west to Broadway via 42nd Street. This new plan, formally adopted on January 14, 1897, consisted of a line from City Hall north to Kingsbridge and a branch under Lenox Avenue and to Bronx Park, to have four tracks from City Hall to the junction at 103rd Street. The "awkward alignment...along Forty-Second Street", as the commission put it, was necessitated by objections to using Broadway south of 34th Street. Legal challenges were resolved in 1899.

The city decided to issue rapid transit bonds outside of its regular bonded debt limit and build the subways itself; it contracted with the Interborough Rapid Transit Company (which by that time ran the elevated lines in Manhattan) to equip and operate the subways, sharing the profits with the city and guaranteeing a fixed five-cent fare.nycsubway.org — The Dual System of Rapid Transit (1912)

BRT

Starting in 1899, the Brooklyn Rapid Transit Company (BRT; 1896–1923) and Brooklyn–Manhattan Transit Corporation (BMT; 1923–1940) operated rapid transit lines in New York City — at first only elevated railways and later also subways.

The BRT was incorporated on January 18, 1896. It took over the bankrupt Long Island Traction Company in early February, acquiring the Brooklyn Heights Railroad and the lessee of the Brooklyn City Rail Road. It then acquired the Brooklyn, Queens County and Suburban Railroad. The BRT took over the property of a number of surface railroads, the earliest of which, the Brooklyn, Bath and Coney Island Railroad or West End Line, opened for passenger service on October 9, 1863, between Fifth Avenue at 36th Street at the border of Brooklyn City and Bath Beach in the Town of Gravesend, New York. A short piece of surface route of this railroad, the BMT West End Line (today's ) on the west side of the Coney Island Complex north of the Coney Island Creek, is the oldest existing piece of rapid transit right-of-way in New York City and in the U.S., having opened on June 8, 1864.

On January 30, 1899, the Brooklyn Union Elevated Railroad was incorporated; it acquired the property of the bankrupt Brooklyn Elevated Railroad on February 17. The BRT gained control a month later, on March 25, and leased the elevated company to the Brooklyn Heights Railroad, which was until then solely a street railway company. The other elevated company in Brooklyn, the Kings County Elevated Railway, was sold under foreclosure to the BRT on July 6, 1899. Initially the surface and elevated railroad lines ran on steam power, but between 1893 and 1900 the lines were converted to run on electricity. An exception was the service on the Brooklyn Bridge. Trains were operated by cables from 1883 to 1896, when they were converted to electric power."Early Rapid Transit in Brooklyn, 1878 to 1913", nycsubway.org