The London Underground uses two types of rolling stock: smaller deep-level tube trains and larger sub-surface trains of a similar size to those on British main lines, both running on standard gauge tracks. New trains are designed for the maximum number of standing passengers and for speed of access to the cars.
The first underground passenger services started in 1863 when the Metropolitan Railway opened using steam locomotives hauling gas-lit wooden carriages, braked from a guards' compartment. In 1890, the City and South London Railway opened the world's first deep-level tube railway, using electric locomotives pulling carriages with small windows, nicknamed "padded cells". Other tube railways opened in the early 20th century using electric multiple units known as 'gate stock', as access to them was via lattice gates at each end of the car. The earlier railways had electrified the underground sections of their lines by 1907.
Pneumatic sliding doors were introduced on tube trains in 1919 and sub-surface trains in the late 1930s. Until the early 1960s an electric locomotive was exchanged for a steam locomotive on Metropolitan line services beyond . The Victoria line opened in the late 1960s using automatic train operation (ATO), and the last trains ran with a guard in 2000. , the Central, Jubilee, and Northern lines also use forms of ATO, the latter two using a system called TBTC (transmission-based train control).
The older sub-surface trains were replaced between 2010 and 2017 by new air-conditioned S Stock, and the replacement of the 1972 Stock and the 1973 Stock on the Bakerloo and Piccadilly lines respectively is currently under consideration. They will be replaced by the New Tube for London.
Current stock London Underground trains come in two sizes, larger sub-surface trains and smaller deep-tube trains. Since the early 1960s all passenger trains have been electric multiple units (EMUs) with sliding doors. A train last ran with a guard in 2000. All lines use fixed-length trains with between six and eight cars, except for the Waterloo & City line, which uses four cars. New trains, which are designed for maximum number of standing passengers and for speed of access to the cars, have regenerative braking and public address systems.
Since 1999, all new stock has had to comply with accessibility regulations that require such things as access and room for wheelchairs, and the size and location of door controls. All underground trains are required to comply with The Rail Vehicle Accessibility (Non Interoperable Rail System) Regulations 2010 (RVAR 2010) by 2020.
Stock on sub-surface lines is identified by a letter (such as S Stock, used on all subsurface lines), while tube stock is identified by the year in which it was designed (such as 1996 Stock, used on the Jubilee line).
London Underground lines Line Stock Image Introduced Refurbishment Driving Number of cars Car Length Length Seats Capacity Fleet sizeNotesBakerloo 1972 1972–1974 OPO 7 DM 16.091 m (52 ft 9.5 in) T/UNDM 15.977 m (52 ft 5.0 in) 268 851 36 Central 1992 1993–1995 ATO/ATP 8 16.25 m (53 ft 4 in) 272 1047 85 CircleS7 2013–2014 —7 17.44 m (57 ft) (DM) 15.43 m (51 ft) (NDM)2561045 113 (shared between lines) District 2013–2017Hammersmith & City 2012–2014Jubilee 1996 2017–2019 ATO/TBTC 17.77 m (58 ft 4 in) 234 964 63 Metropolitan S8 2010–2012 — 8 17.44 m (57 ft) (DM) 15.43 m (51 ft) (NDM) 306 1176 58 Northern 1995 1998–2000 2013–2015 ATO/TBTC 6 17.77 m (58 ft 3.6 in) 248 752 106 Piccadilly 1973 1975–1978 1996–2001 OPODM 17.473 m (57 ft 3.9 in) UNDM/T 17.676 m (57 ft 11.9 in) 228 798 86.5 Victoria 2009 2009–2011 — ATO/DTG-R 8 16.595 m (54 ft 5.3 in) (trailing cars) 16.345 m (53 ft 7.5 in) (all others) 288 986 47 Waterloo & City 1992 1993 2006 OPO 4 16.25 m (53 ft 4 in) 136 506 5
Future development plans 2024 Stock
The Deep tube programme (DTP) originally covered the replacement of the trains and signalling on the Bakerloo and Piccadilly lines. It has been expanded to cover rolling stock requirements arising from the extension of the Northern line to Battersea, the eventual replacement of Central Line trains and proposed increased service frequency on the Northern and Jubilee lines. The EVO tube concept design, a lighter articulated train with walk through cars, was introduced early in 2011. In early 2014 the Bakerloo, Piccadilly, Central and Waterloo & City line rolling stock replacement project was renamed New Tube for London (NTfL) and moved from its feasibility stage to the design and specification stage. In late 2024 the first NTFL trains were delivered for storage and testing in London.
The proposal introduces fully automated trains and signalling to replace 1973 Stock which was due for replacement in 2014 but was deferred to 2024. It also plans to replace 1972 Stock due to the old age of the stock, which was actually due for replacement in 2020 but was delayed due to COVID-19 pandemic. It also plans to replace 1992 Stock but due to the young age it was being refurbished. The fully automated trains may not have drivers. The ASLEF and RMT trade unions that represent the drivers strongly oppose this, saying that it would be unsafe. Internal investigations from TfL revealed that the upgrades required to operate driverless trains were economically unviable.
History Steam locomotives Metropolitan Railway
Concern about smoke and steam in the tunnels led to trials before the line opened with an experimental "hot brick" locomotive nicknamed Fowler's Ghost. This was unsuccessful and the first public trains were hauled by broad gauge GWR Metropolitan Class condensing 2-4-0 tank engines designed by Daniel Gooch. These were followed by standard gauge Great Northern Railway locomotives and then by the Metropolitan Railway's own standard gauge locomotives. All tank engines, these locomotives were classified by letters of the alphabet. Initially eighteen A Class (4-4-0) were ordered in 1864. By 1870 a total of forty-four had been built. In 1885, an improved version was ordered and twenty-two B Class were built.
From 1891, more locomotives were needed for work on the line from into the country. Four C Class (0-4-4) were received in 1891 and six D Class (2-4-0) in 1894. From 1896 to 1901 seven E Class (0-4-4) locomotives were built to replace the A class on this line. In 1901 the Met also received four F Class (0-6-2), a freight variant of the E Class. Not all these new locomotives were fitted with the condensing equipment needed to work south of Finchley Road.
The need for more powerful engines meant in 1915 four G Class (0-6-4) arrived, named after people or places associated with the Metropolitan Railway. Eight capable H Class (4-4-4) were built in 1920 for express passenger services, replacing the C and D class locomotives. In 1925, six freight K Class (2-6-4) locomotives arrived. These were out of gauge south of Finchley Road.
District Railway
The first services were run by the Metropolitan Railway. In 1871 the District Railway began running its own services with locomotives that were identical to the Metropolitan Railway A Class already in use. Twenty were supplied initially, and by 1905 the District had 54 locomotives. After the railway had been electrified by 1907 all but six of the steam locomotives had been sold. In 1925 two locomotives were retained for departmental use.
London Passenger Transport Board In November 1937, the later Metropolitan Railway G, H and K Class steam locomotives were transferred to the London and North Eastern Railway (LNER), who took over all freight workings and became responsible for hauling passenger trains with steam locomotives north of Rickmansworth. From the early 1940s, these were replaced by ex Great Central Railway locomotives, now classified LNER Class A5. These were replaced in 1948 by LNER L1s. Former LMS locomotives replaced the L1s ten years later, when the joint line was transferred to British Railways' London Midland Region. Steam working ended on passenger trains in 1961, after electrification and the introduction of A Stock electric multiple units.
Electric locomotives
The City and South London Railway tube line opened in 1890 with electric locomotives hauling carriages. Initially the locomotive could haul three carriages at an average ; the trains were air braked, their reservoirs topped up at Stockwell. Fourteen locomotives were initially built, soon supplemented by more. When the railway was extended in 1900 a further 30 locomotives to an improved design were built, and 10 of the first generation rebuilt. In 1923 the railway was closed for reconstruction and tunnel enlargement, and the line reopened using newly built Standard Stock electrical multiple units.
When the Central London Railway opened in 1900, carriages were hauled by electric locomotives. However, the 44-ton locomotives had a high unsprung weight of 34 tons, and these caused noise and vibrations that could be felt at ground level. In 1902–03 the carriages were reformed into multiple units using a control system developed by Frank Sprague in Chicago.
The District Railway used electric locomotives on electrified underground lines that were exchanged for steam locomotives to continue over unelectrified track. Ten were built in 1905, and these operated in pairs, initially used to haul London and North Western Railway passenger trains on their Outer Circle route between Earl's Court and Mansion House. From 1910 trains from the London, Tilbury and Southend Railway were extended over the District, the steam locomotives being exchanged for electric ones at Barking. These locomotives were scrapped after the service was withdrawn in 1939.
Similarly Metropolitan Railway electric locomotives were used with conventional carriage stock. On the outer suburban routes an electric locomotive was used at the Baker Street end that was exchanged for a steam locomotive en route. The first ten had a central cab and were known as camel-backs, and these entered service in 1906. A year later another ten units with a box design and a driving position at both ends arrived. These were replaced by more powerful units in the early 1920s. The locomotives were withdrawn from passenger service after electrification to Amersham was completed in 1961, although three were kept as shunters.
Carriages
The Metropolitan Railway opened in 1863 with gas-lit wooden carriages hauled by steam locomotives. Lighting was provided by gas — two jets in first class compartments and one in second and third class compartments. Initially the carriages were braked with wooden blocks operated from the guards' compartments at the front and back of the train, giving off a distinctive smell. The Metropolitan and District railways both used loco-hauled carriages exclusively until they electrified in the early 20th century. The District railway replaced all its carriages with electric multiple units. The Metropolitan still used loco-hauled carriages on the outer suburban routes, where an electric locomotive at the Baker Street end was exchanged for a steam locomotive en route. Carriages were introduced in the later years of the 19th century that gave a better ride quality, steam heating, automatic vacuum brakes, electric lighting and upholstered seating in all classes.