New Tube for London
New tube for london final design.jpg
Finalised concept design of the New Tube for London
ManufacturerSiemens Mobility
Built at
Family nameInspiro
ConstructedUnder construction
Formation9 cars per train[1]
Capacity1,076 per train (268 seated)[1]
Line(s) servedPiccadilly
Train length113.7 m (373 ft 38 in)[1]
Width2.648 m (8 ft 8+14 in)[1]
Height2.844 m (9 ft 3+1516 in)[1]
Maximum speed100 km/h (62 mph)[1]
Traction systemIGBTVVVF (Siemens SIBAC)[citation needed]
Power output2.5 MW (3,400 hp)[1]
Electric system(s)630–750 V DC third and fourth rail[1]
Current collector(s)Contact shoe
Stock typeDeep-level tube
 London transport portal

The New Tube for London (NTfL) is a type of London Underground train to be built by Siemens as part of its Inspiro family at Siemens's factories in Goole (East Yorkshire) and Vienna, Austria.[2]

An initial batch of 94 nine-car trains has been ordered at a cost of £1.5bn to replace 1973 Stock trains on the Piccadilly line, with options for a total of 250 trains allowing replacement of all existing trains on the deep-level Central, Waterloo & City and Bakerloo lines. Trains will enter service from 2025, firstly on the Piccadilly line.[3][4][5] Trains will enter service with a train operator but equipped to allow for driverless operation in the future.[6]



In the late 1990s, the Labour government initiated a public–private partnership (PPP) to reverse years of underinvestment in London Underground.[7] Under the PPP contracts, two private consortiums (Metronet and Tube Lines) would maintain, renew and upgrade London Underground infrastructure over a period of 30 years from 2003.[8] As part of the upgrade work, new rolling stock was to be ordered.[9][10]

Tube Lines planned to order 93 new Piccadilly line trains, which would enter service by 2014.[10] In January 2007, Tube Lines started the process of ordering new Piccadilly line trains, by querying if train manufacturers would be interested in supplying them.[11] Contract award was anticipated for 2008, and trains would enter service on the Piccadilly line in 2014.[11] Following the delivery of 2009 Stock and S Stock trains in the 2010s, Metronet planned to order 24 new Bakerloo line trains, which would enter service by 2019.[9]

However, Metronet collapsed in 2007 after cost overruns,[12] and Transport for London (TfL) bought out the Tube Lines consortium in 2010, formally ending the PPP.[13]

Feasibility and initial planning

Following the collapse of the PPPs, TfL began planning the modernisation of Underground lines not started by the PPP. This project would include the eventual replacement of trains, new signalling and other upgrades to the Piccadilly, Central, Waterloo & City and Bakerloo lines.[14] This would complete the modernisation of Underground lines since the formation of TfL in 2000.[15]

According to TfL, existing trains on the Bakerloo and Piccadilly lines are approaching the end of their useful lives, and the 1992 Stock used on the Central and Waterloo & City lines is significantly less reliable than more modern rolling stock.[14][16]

Replacement of these older trains with open gangway rolling stock – similar to the S Stock used on the Underground's subsurface lines – would increase passenger capacity, with new automatic signalling increasing capacity further.[14] Although open gangway train concepts were considered in the late 1990s,[17] the Bombardier 2009 Stock did not utilise this technology. New trains would also have air conditioning, which existing deep-level trains lack.[14]

In 2011, Siemens presented "EVO" – a conceptual articulated train with walk-through cars, that would be 30 tonnes lighter, consume 17 per cent less energy and have 11 per cent more passenger capacity than existing trains.[18][19][20] A mock-up of this Siemens Inspiro design was exhibited at The Crystal between October 2013 and January 2014.[20] Siemens also proposed building the new train in the UK, after being criticised for building the Class 700 Thameslink trains in Germany.[21]

Potential of driverless operation

New trains would have the potential to be driven automatically without a train operator, which would save operating costs and prevent disruption during strikes.[6][22] Unattended train operation would require the installation of platform screen doors, a substantial additional cost.[14] The ASLEF and RMT trade unions that represent drivers strongly oppose the introduction of driverless trains, saying it would affect safety.[23][24]

In 2020, a leaked TfL study said that the upgrade work required for unattended train operation - including platform screen doors and a safety walkway in tunnels[25] - would cost around £7bn, concluding that "the financial payback is negative". The study also indicated that automatically driven trains with a member of staff present on board (similar to the Docklands Light Railway) offers "reasonable value for money."[26] However, the Department for Transport has pushed for the introduction of driverless trains as a precondition of any future long term funding deal for TfL.[27]

New Tube for London

Mockup of Siemens' "evo" concept proposal
Mockup of Siemens' "evo" concept proposal

In early 2014, the project was named New Tube for London (NTfL) and moved from a feasibility stage to the design and specification stage. A TfL feasibility study showed that new generation trains and re-signalling could increase capacity:

NTfL capacity increase forecast[14]
Line Capacity increase tph Notes
Piccadilly 60% 36
Central 25% 36
Waterloo & City 50% Requires track remodelling at Waterloo
Bakerloo 25% 27

Overall, the project is estimated to cost a total of £16 billion, with a benefit/cost ratio of 4.2 to 1.[6][28] The Piccadilly line would be the first to be upgraded, given the age of its rolling stock.[29] Other lines would then be upgraded over a period of around 10 years.

Bidding process

In early 2014, TfL invited train manufacturers to make expressions of interest in the Official Journal of the European Union.[30][31] TfL also commissioned industrial designers PriestmanGoode to create a conceptual design vision that would be used by the train manufacturers.[32][33][34] Unveiled in October 2014 to high acclaim,[35] the design included several features not seen before on the deep level tube, including walk-through carriages and air conditioning.[36][37]

In late 2014, TfL published a shortlist of manufacturers who had expressed an interest in supplying new trains – Alstom, Siemens, Hitachi, CAF and Bombardier.[36] The invitation to tender for the trains was issued in January 2016,[30][31] with a plan to award the contract in 2016, with trains entering service in 2023.[29] During the tender period, Bombardier and Hitachi formed a joint venture (JV) and CAF chose not to submit a bid. Three bids (Alstom, Siemens, Hitachi/Bombardier JV) were submitted in September 2016.[15] All bidders proposed to construct a UK factory, or use existing UK factories to build the trains.[38][39]

Contract award and future contract options

Since TfL could not afford 250 new trains and upgraded signalling, it decided to buy only 94 trains for the Piccadilly line and relegate future train purchases to contract options.[40][41][15] In 2019, TfL raised £1bn to buy the Piccadilly line trains by selling and leasing back Class 345 Crossrail trains.[42]

In total, 250 trains could be ordered throughout the lifetime of the Deep Tube Upgrade Programme, comprising 100 trains for the Piccadilly line, 40 for the Bakerloo line, 100 for the Central line and 10 for the Waterloo & City line.[5] Future trains would be adapted to meet the requirements of lines, with the potential of active steering of bogies and more/fewer cars per trainset as required.[43]

Siemens 'InspiroLondon'

In June 2018, the Siemens Mobility Inspiro design was selected, with 94 trains ordered in a £1.5 billion contract.[44] In July 2018, the award was challenged in the High Court by the Hitachi/Bombardier JV.[45] The challenge was unsuccessful; Siemens was awarded the contract in November 2018.[46]

Around 50 per cent of the trains will be assembled in a new factory in Goole, East Riding of Yorkshire,[39] with the remainder to be built at an existing Siemens factory in Vienna, Austria while the Goole factory is constructed.[2] In July 2020, Prime Minister Boris Johnson visited the Goole site to mark the start of construction of the factory.[47][48] Full manufacturing of the trains in Austria was due to commence in August 2021, with first deliveries to London taking place from 2024.[49]

Despite the lack of resignalling,[50] the purchase of new trains will still increase the capacity of the Piccadilly line, with 27 trains per hour at peak times by 2027.[3] Trains will enter service with a train operator. However, resignalling of the line could allow for driverless operation in future.[6]

Features of the new train include:[51][52][53][43]

Siemens has branded the train "Inspiro London",[4] although some sources have named it "2024 Stock",[54] following the existing naming precedent. As of March 2021, the official name of the train has not been confirmed by TfL.[4]

Initially, deliveries were to begin in 2023, with entry into service in 2024.[55] As of March 2021, the delivery schedule had slipped; the trains are expected to enter service on the Piccadilly line in 2025.[2][4] Improvements to service levels would follow in 2027.[3][49]


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