The Metropolitan line is part of the London Underground, coloured Magenta on the Tube map. It was the first underground railway (or subway) in the world, opening on 10 January 1863 (however, parts of that initial section are no longer served by the Metropolitan line, but by the Hammersmith & City, District and Circle lines). The main line runs from Aldgate in the City of London to Amersham, with branch lines to Uxbridge, Watford and Chesham. For the initial section of the line the rails are in tunnel for much of the way; beyond Baker Street, at Finchley Road the line runs in the open. Out of the 34 stations served, only 9 are underground. It is now the least used line on the Underground for its length of track; ironically it is the oldest line and initially covered the bulk of the Underground system. Today it is the ninth busiest line on the network.
The four-track layout for part of the distance — between Wembley Park and Moor Park — allows for the running of express or "fast" services to the outer suburbs. Baker Street is the terminus for some trains, with others continuing into the City to Aldgate.
It is the fastest line on the London Underground network - Before the late 1990s/early 2000s, the fast line north of Harrow-on-the-Hill was . However, the Metropolitan stock has now been limited to but the stock is still the fastest. Line speeds have dropped accordingly with the majority of the line north of Finchley Road limited to , and where National rail services run on the line it is .
Between its opening and the 1930s the railway was expanded until its total mileage exceeded 90, most of it progressively electrified from 1905. In 1933 the Metropolitan Railway was taken over by the London Passenger Transport Board, becoming the Metropolitan line of the London Underground. The line was successively rationalised during this period. The section north-west of Aylesbury was closed in 1936 (though services did get to Quainton Road again between 1943 and 1948). In the same year a service extension from Whitechapel to Barking was implemented along the District line tracks. In 1939 the Stanmore extension was taken over by the Bakerloo line (it now forms the original core of the Jubilee line). In 1948 it was nationalised, along with the rest of the Underground.
Steam-hauled passenger trains ran north of Rickmansworth until 1961 and maintenance trains until 1972. A major modernisation of the that arm of the network line took place by 1960. The service was totally electrified to Amersham and Chesham, while the service beyond Amersham was withdrawn in September 1961, along with the steam passenger service. The line north of Harrow was quadrupled to Northwood Hills by 1961 and Croxleyhall Junction (north of Moor Park) by 1962. Prior to that local and semi-fast services from Aylesbury to Harrow had shared the double-track with main line expresses of the former Great Central route.
Another major change took place in 1988, when the Hammersmith & City line and East London line — which already had well-defined individual identities — were split off from the Metropolitan line to be run separately. The Metropolitan line is now confined to its northern extension from Baker Street, through the area that came to be known as "Metro-land", plus its original track to Aldgate, running through the tunnels opened by the Metropolitan Railway back in 1868. The East London line shared stock with the Metropolitan line until its closure in 2007 for conversion to London Overground. While there is no passenger interchange between the two lines, there is a physical connection (via Aldgate East), although this is expected to be redundant once the ELL re-opens, as it will have its own stock.
In 1998, the Metropolitan line was partly privatised in a controversial Public-Private Partnership. It is now part of the "Sub-Surface Railways" group, managed along with the Circle, Hammersmith & City and District lines by the Metronet consortium.
The Metropolitan line's influence on underground railways world-wide has been immense. The Paris Métro took its name, in full Chemin de fer métropolitain, from the Metropolitan line. This is the origin of the term metro.
The current rolling stock in use on the Metropolitan line is the sub-surface gauge A Stock built by Cravens in Sheffield, which were shared with the East London line until 2007. While it ran in service with unpainted aluminium bodywork for many years, since refurbishment the stock has received the now standard white and blue Underground livery, with red ends. Metropolitan line services are usually formed of two four-car units coupled together for a total of eight cars, although the Chesham shuttle service is served by four-car trains, as was the East London Line.
The A Stock trains were built in the early 1960s and are now the oldest trains operating on the London Underground. They replaced a wide variety of older rolling stock, including trains with hinged doors and compartments (T Stock electric multiple units for Watford services and locomotive-hauled carriages for Aylesbury services), as well as London Underground P stock (built in 1937) and F Stock (built in 1920) used on Uxbridge services. The A Stock trains are due to be replaced by the new S Stock.
The TFL line diagram is available online.
The Metropolitan line diverges from the Circle/Hammersmith & City lines just east of Baker Street station, where they use separate platforms, at a roughly 45 degree angle to the Circle/Hammersmith & City platforms.
At Wembley Park, the Metropolitan lines split from two tracks to four, with the faster lines on the outside. Fast services (typically to Amersham) and semi-fast services (typically to Watford) do not stop at Preston Road or Northwick Park. During the peaks, they also skip Wembley Park.
At Harrow, the line splits into two branches — the main line to Watford, Amersham and the Uxbridge branch.
After Harrow-on-the-Hill the lines are re-arranged into two parallel pairs, the slow (the northerly pair) and the fast. The fast lines are also shared with the National Rail line to Aylesbury (operated by Chiltern Railways) which had hitherto run parallel. The stations between Harrow-on-the-Hill and Moor Park (exclusive) only have platforms on the slow lines, and can only be stopped at by slow and semi-fast services, which usually run to Watford. At Moor Park the line splits, with the fast line forming the main line towards Amersham and the slow line heading off towards Watford.
Here trains either continue to Amersham or, during peak hours, go straight through on a separate branch to Chesham. At all other times there is a shuttle between Chalfont & Latimer and Chesham, which involves a change from Amersham trains. The service frequency between Chalfont & Latimer and Chesham is roughly every 30 minutes.
Verney Junction Branch
The Metropolitan line, unlike other London Underground lines, operates express services (the Piccadilly line runs a fast service between Hammersmith and Turnham Green/Acton Town, but the intermediate stations are served by the District line, and so all Piccadilly line trains stop at all regular Piccadilly line stations on their route, in the same way as the Metropolitan by-passes Jubilee line stations between Finchley Road and Wembley Park). Fast services, usually to Amersham, call at Baker Street, Finchley Road, Wembley Park, Harrow-on-the-Hill, Moor Park and then all stations. There are also semi-fast services, usually in the peak, which use the fast stopping pattern as far as Harrow-on-the-Hill, but then run all stations, usually to Watford.
The current off-peak service pattern is as follows:
London Underground have proposed reducing the service to Amersham from 4tph to 2tph, while Chesham will be served by 2tph to London.
During peak hours the services vary much more. Trains can run through from Aldgate to any destination, and each terminus gets a mixture of fast and semi-fast – which generally don't stop at Wembley Park – and all stations services. Through trains also run between Chesham and London. There are also a few early-morning/late-evening trains from Rickmansworth to Watford.
Transport for London and Hertfordshire County Council are developing plans to divert the line from the current Watford station and re-route it over the disused Croxley Green branch line to Watford Junction.
It was envisaged in 2005 that the link would be operational by 2010, but difficulties in securing funding caused the project to be postponed.
The current Watford station is located in a housing estate by Cassiobury Park, rather than serving the centre of Watford. Should the project go ahead, the station would close. A new station would be provided at Ascot Road and Watford West would be refurbished and reopened.