By World War I, electric underground railways were being used in Athens, Berlin, Boston, Buenos Aires, Budapest, Glasgow, Hamburg, Istanbul, Liverpool, New York City, Paris, and Philadelphia.
In the 21st century, China became the world's leader by number of rapid transit systems as well as the fastest growth of such systems,[citation needed] and many other Asian countries began construction of their own rapid transit systems.While smoke was a major problem for urban railways in tunnels, it was less of a problem in steam-hauled elevated railways, the first of which opened in New York City in 1870.
Electric traction was more efficient, faster and cleaner than steam and the natural choice for trains running in tunnels and proved superior for elevated services.
It was worked by steam trains and despite the creation of numerous vents, was unhealthy and uncomfortable for passengers and operating staff.
Smoke collected in the tunnels, leading to proposals to build pneumatic or cable-hauled railways to overcome this problem between 1863 and 1890, though none were successful.
It featured an extensive system of suburban branches to the northwest (extending into the adjoining countryside), the west, the southwest and the east that was mostly completed by 1904.
The presence of the "El" helped Liverpool earn the nickname "Britain's North American City".
[4] The LOR was demolished in 1957 and Liverpool is served today by a partially underground urban rail network known as Merseyrail, which includes the former Mersey Railway which opened in 1886.
A major breakthrough in the development of electrically driven rapid transit occurred when the American inventor Frank J. Sprague successfully tested his system of multiple-unit train control (MUTC) on the South Side Elevated Railroad (now part of the Chicago 'L') in 1897.
MUTC, which allowed all the motors in an entire train to be controlled from a single point, freed rapid transit systems from dependence on locomotive-hauled coaches.
Istanbul's Tünel (F2) which was opened in 1875, second-oldest extant subterranean urban rail line in the world, after the London Underground (1863).
The M1 line became an IEEE Milestone due to the radically new innovations in its era: "Among the railway’s innovative elements were bidirectional tram cars; electric lighting in the subway stations and tram cars; and an overhead wire structure instead of a third-rail system for power.
[7] The 10.4 kilometres (6.5 mi) Glasgow Subway in Scotland opened the same year and used cable haulage until it was electrified in 1935.
Its full name was the Chemin de Fer Métropolitain, a direct translation into French of London's Metropolitan Railway.
The Athens-Piraeus Electric Railway was built as a steam-hauled suburban line in 1869 and acquired an underground section in the capital in 1874.
New York City built its first rapid transit line, the West Side and Yonkers Patent Railway, in 1868.
The Hudson and Manhattan Railroad, which opened a subway tunnel in Manhattan in 1908 and connected with New Jersey, remained a separate railroad company, later coming under the control of the Port Authority of New York and New Jersey as the Port Authority Trans-Hudson (PATH).
The first Chicago L, the South Side Elevated Railroad began operations in 1892, over tracks used by the Green Line over 125 years later.
Tunis has a tram system that is referred to as a métro léger (meaning "light rail")[9] despite not being rapid transit.
Other major Japanese cities with subway systems are Yokohama, Sapporo, Kobe, Kyoto, Fukuoka, Nagoya and Sendai.
Pyongyang in North Korea notably has a well adorned and deep metro with non-geographical names of stations (unique in the world) and was built to serve as a bomb shelter in case of a war.
Delhi, Mumbai, Bengaluru, Chennai, Kochi, Hyderabad, Nagpur, Jaipur and Ahemdabad built metros afterwards.
Patna and other cities have hired engineers and civil planners to plan the locations of future metro lines.
The network currently has 26 stations (2 underground and 24 elevated) and is 27 kilometres long and is the first rapid transit line in Pakistan.
It was the world's first heavy rail system to feature platform screen doors on its underground stations.
Other systems in the post-Soviet States include Saint Petersburg (1955), Kiev (1960), Tbilisi (1966), Baku (1967), Kharkov (1975), Tashkent (1977), Yerevan (1981), Minsk (1984), Nizhny Novgorod (1985), Novosibirsk (1986), Samara (1987), and Yekaterinburg (1991), Almaty (2011).
Bay Area Rapid Transit (BART) in the San Francisco Bay Area and Metropolitan Atlanta Rapid Transit Authority (MARTA) both opened in 1972, and the capital's Washington Metro in Washington, D.C. in 1976 as part of changing attitudes towards transportation in the United States.
In autumn 2005, several politicians including Los Angeles mayor Antonio Villaraigosa indicated a desire to complete the originally conceived subway route along Wilshire Boulevard to West Los Angeles and Santa Monica; the D Line Extension (after the branch's former color indicator) is under construction and planned to open in phases until 2027.
It is the Caribbean's first rapid transit system,[13] opening in 2004 The five largest Australian cities have suburban railway networks, but all except Perth have long-distance passenger and/or freight traffic on some lines.
In Brazil, the first underground rapid transit service opened in 1974 in São Paulo, and now the Metrô carries some 4 million passengers on an average weekday.