London Underground S7 and S8 Stock

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "London Underground S7 and S8 Stock" – news · newspapers · books · scholar · JSTOR (December 2022) (Learn how and when to remove this message)

London Underground S7 and S8 Stock
A Metropolitan line S8 Stock at Amersham in 2013
The interior of a Circle line S7 Stock train
In service	31 July 2010 − present
Manufacturer	Bombardier Transportation
Built at	Derby Litchurch Lane Works, Derby, England
Family name	Movia
Replaced	A60/62 Stock C69/77 Stock D78 Stock
Constructed	2008–2017
Entered service	31 July 2010 (S8) 6 July 2012 (S7)
Number built	192 trains (133 S7, 59 S8)[1]
Number in service	192 trains[1]
Formation	7 cars per train (S7) 8 cars per train (S8)
Fleet numbers	S7: 301/302–567/568 S8: 001/002–115/116
Capacity	1,209 (S7) 1,350 (S8)
Operators	London Underground
Depots	Ealing Common Neasden Upminster Hammersmith (stabling only) Lillie Bridge (stabling only)
Lines served	S7: Circle District H. & City S8: Metropolitan
Specifications
Car body construction	Aluminium
Train length	S7: 117.45 m (385 ft 4 in) S8: 133.68 m (438 ft 7 in)
Car length	18.15 m (59 ft 7 in) (DM) 16.23 m (53 ft 3 in) (NDM) [2]
Width	2.92 m (9 ft 7 in)[3]
Floor height	1,005 mm (39.6 in)
Entry	Level
Doors	6 per car (3 per side)
Wheel diameter	770–710 mm (30–28 in) (new–worn)[4]
Wheelbase	2.08 m (6 ft 10 in)[4]
Maximum speed	100 km/h (62 mph)
Traction system	Bombardier MITRAC IGBT–VVVF
Traction motors	3-phase AC induction motor
Acceleration	1.3 m/s2 (2.9 mph/s)
Deceleration	1.4 m/s2 (3.1 mph/s)
Electric system(s)	630–750 V DC fourth rail
Current collector(s)	Contact shoe
Bogies	Bombardier FLEXX Metro 1200 SSL[4]
Safety system(s)	Communications-based train control Tripcock
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge

The London Underground S7 and S8 Stock, commonly referred to as S Stock, is a type of passenger train running on the London Underground's subsurface lines since 2010. Manufactured by Bombardier Transportation's Derby Litchurch Lane Works, the S Stock was ordered to replace the A60, A62, C69, C77 and D78 stock on the Metropolitan, District, Hammersmith & City, and Circle lines, which all dated from the 1960s and 1970s.

The order was for a total of 192 trains (1,403 cars), and consisted of two types, S7 Stock for the Circle, District and Hammersmith & City lines, and S8 Stock for the Metropolitan line, with differences in the arrangement of seating and number of cars. Both types have air-conditioning and lower floors to ease accessibility for disabled people, and also have open gangways to allow passengers to move from one car to another whilst the train is moving. The order was said to be the biggest single rolling-stock order in Britain at a cost of £1.5 billion.

Passenger service began on the Metropolitan line in July 2010, the Hammersmith & City line in July 2012, and the Circle and District lines in September 2013. The S Stock completely replaced the A Stock on the Metropolitan line in September 2012, and the C Stock on the Circle and Hammersmith & City lines in February 2014, and on the Edgware Road branch of the District line in June 2014; it fully replaced the D Stock on the rest of the District line in April 2017.