London Underground

London Underground, often shortened to the Underground is a rapid transit system in the United Kingdom, serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex. It incorporates the oldest section of underground railway in the world, which opened in 1863 and now forms part of the Circle, Hammersmith & City, and Metropolitan lines; and the first line to operate electric trains, in 1890, now part of the Northern line.
The Underground system is also colloquially called the Tube. As commonly used today both by Londoners and in most official publicity, this term embraces the entire system. Originally, though, it applied only to the deep-level lines with trains of a smaller and more circular cross-section, and served to distinguish them from the sub-surface "cut-and-cover" lines that were built first and originally used steam locomotives.
The earlier lines of the present London Underground network were built by various private companies. They became part of an integrated transport system in 1933 when the London Passenger Transport Board (LPTB) or London Transport was created. The underground network became a separate entity in 1985, when the UK Government created London Underground Limited (LUL). Since 2003 LUL has been a wholly owned subsidiary of Transport for London (TfL), the statutory corporation responsible for most aspects of the transport system in Greater London, which is run by a board and a commissioner appointed by the Mayor of London.
The Underground serves 270 stations and has 402 kilometres (250 mi) of track, 45 per cent of which is underground. It is the second largest metro system in the world in terms of route miles, after the Shanghai Metro and part of the largest system in terms of route miles when taken together with the Docklands Light Railway and the London Overground. It also has one of the largest numbers of stations. In 2007, more than one billion passenger journeys were recorded, making it the third busiest metro system in Europe, after Moscow and Paris. The tube is an international icon for London, with the tube map, considered a design classic, having influenced many other transport maps worldwide. Although also shown on the Tube map, the Docklands Light Railway (DLR) and London Overground are not part of the London Underground network.
Currently, 86% of operational expenditure on the London Underground is covered by passenger fares. Almost all London Underground trains currently lack air-conditioning, which leads to the network getting very hot in the summer, although plans are under way to mitigate this problem with new air-conditioned trains and other schemes. Because of engineering work being carried out under the 2010–2012 upgrade plan, lines were regularly closed during weekends.

First tube lines

Following advances in the use of tunnelling shields, electric traction and deep-level tunnel designs, later railways were built deeper underground. This caused much less disruption at ground level, and it was therefore cheaper than and preferable to the cut-and-cover construction method.
The City & South London Railway (C&SLR, now part of the Northern Line) opened in 1890, between Stockwell and the now closed original terminus at King William Street. It was the first "deep-level" electrically operated railway in the world. By 1900 it had been extended at both ends, to Clapham Common in the south and Moorgate Street (via a diversion) in the north. The second such railway, the Waterloo and City Railway (W&CR), opened in 1898. It was built and run by the London and South Western Railway.
On 30 July 1900, the Central London Railway (now known as the Central Line) was opened, operating services from Bank to Shepherd's Bush. It was nicknamed the "Twopenny Tube" for its flat fare and cylindrical tunnels;the "tube" nickname was eventually transferred to the Underground system as a whole. An interchange with the C&SLR and the W&CR was provided at Bank. Construction had also begun in August 1898 on the Baker Street & Waterloo Railway, but work came to a halt after 18 months when funds ran out.

Nationalisation

On 1 January 1948, London Transport was nationalised by the Labour government, together with the four remaining main-line railway companies, and incorporated into the operations of the British Transport Commission (BTC). The LPTB was replaced by the London Transport Executive (LTE). This brought the Underground under the direct remit of central government for the first time in its history. The BTC prioritised the reconstruction of its main-line railways over the maintenance of the Underground network. The unfinished parts of the New Works Programme were gradually shelved or postponed.
However, the BTC did authorise the completion of the electrification of the network, seeking to replace steam locomotives on the parts of the system where they still operated. This phase of the programme was completed when the Metropolitan line was electrified to Chesham in 1960. Steam locomotives were fully withdrawn from London Underground passenger services on 9 September 1961, when British Railways took over the operations of the Metropolitan line between Amersham and Aylesbury. The last steam shunting and freight locomotive was withdrawn from service in 1971.
In 1963, the LTE was replaced by the London Transport Board, directly accountable to the Ministry of Transport.

Ticketing

The Underground uses TfL's Travelcard zonal fare system to calculate fares. Greater London is divided into 6 zones; Zone 1 is the most central, with a boundary just beyond the Circle line, and Zone 6 is the outermost and includes London Heathrow Airport. Stations on the Metropolitan line outside Greater London are in Zones 7–9. There are staffed ticket offices, some open for limited periods only, and ticket machines usable at any time. Some ticket machines accept coins, notes and credit cards, some accept coins only, and some accept cards only.
In 2003, TfL introduced the Oyster card, a smartcard with an embedded contactless RFID chip, which travellers can charge up with credit and use to pay for travel. It can also be loaded with Travelcards. Like a paper Travelcard, it can be used on the Underground, the Overground, buses, trams, the Docklands Light Railway, and National Rail services within London. TfL encourages passengers to use Oyster cards instead of Travelcards or cash by implementing significant price differences, so travel by Oyster card is significantly cheaper.
Since GLC days there has been a concessionary fare scheme for disabled London residents and those aged over 60. Since 2006, the scheme has been called the "Freedom Pass" and allows for free travel on TfL-operated routes at all times. It is also valid on National Rail services within London, except between 04:30 and 09:30 on Monday to Fridays on some lines. The pass itself is, in effect, a free Oyster card, though it does not bear that name. Since 2010, the Freedom Pass has inc

Safety
Main articles: Safety on the London Underground and Suicide on the London Underground
Accidents on the Underground network, which carries around a billion passengers a year, are rare. There is one fatal accident for every 300 million journeys. There are several safety warnings given to passengers, such as the 'mind the gap' announcement and the frequent announcements to passengers to keep behind the yellow line. Relatively few accidents are caused by overcrowding on the platforms: staff monitor platforms and passageways at busy times and prevent people entering overcrowded areas.
Most fatalities on the network are suicides. Most platforms at deep tube stations have pits beneath the track. These were originally constructed to aid drainage of water from the platforms, but they also help prevent death or serious injury when a passenger falls or jumps in front of a train.