E231 series

E231 series
An E231-1000 series suburban type train in January 2006
In service	2000–Present
Manufacturer	JR East, Kawasaki Heavy Industries, Tokyu Car Corporation
Built at	Niitsu, Kobe, Yokohama
Replaced	103 series, 113 series, 115 series, 201 series, 205 series, 301 series
Constructed	1998–2011
Number built	2,736 vehicles
Number in service	2,632 vehicles
Number scrapped	104 vehicles (SaHa E230-500)
Formation	5/10/11 cars per trainset
Operator(s)	JR East
Depot(s)	Oyama, Matsudo, Tokyo, Kōzu, Mitaka
Line(s) served	Tokaido Main Line, Yamanote Line, Chuo-Sobu Line, Shonan Shinjuku Line, Joetsu Line, Ryomo Line, Takasaki Line, Utsunomiya Line, Yokosuka Line, Gotemba Line, Tokyo Metro Tozai Line
Specifications
Car body construction	Stainless steel
Car length	20,000 mm (65 ft 7 in)
Width	2,950 mm (9 ft 8 in)
Doors	4 pairs per side 6 pairs per side (SaHa E230)
Maximum speed	120 km/h (75 mph)
Traction system	IGBT-VVVF
Acceleration	2.5 km/h/s, 3.0 km/h/s or 3.3 km/h/s
Deceleration	4.0 km/h/s (4.5 km/h/s for emergency brake)
Train heating	AU725/AU726
Electric system(s)	1,500 V DC overhead
Current collection method	Overhead line
Bogies	DT61 (powered), TR246 (trailer)
Braking system(s)	Regenerative brake, electronically controlled pneumatic brakes
Safety system(s)	ATS-P, ATS-SN, D-ATC
Coupling system	Shibata-type
Multiple working	E233-3000 series
Track gauge	1,067 mm (3 ft 6 in)

The E231 series (E231系, E231-kei^?) is an electric multiple unit (EMU) train type used for commuter and outer-suburban services operated by East Japan Railway Company (JR East) in Japan since 2000.

Trains were manufactured by Tokyu Car Corporation, Kawasaki Heavy Industries and also at JR East's factory at Niitsu in Niigata Prefecture.

The type evolved from the earlier 209 series and E217 series EMUs, with the main visible difference being wider bodies (2,950 mm compared to the 2,800 mm for earlier commuter trains), and the prototype train built in 1998 for trials on the Chuo-Sobu Line was actually classified 209-950 series, later becoming E231-900 series. Full-production E231-0 series trains were subsequently introduced on the Chuo-Sobu Line (10-car sets) and Joban Line (10+5-car sets). Other variants include the 11-car E231-500 series for the Yamanote Line, and the E231-800 series with 2,800 mm wide bodies and end doors for use on Tokyo Metro Tōzai Line inter-running services.

From 2000 onward, the first E231-1000 series outer-suburban variant was delivered for use on Utsunomiya Line and Takasaki Line services north from Ueno Station in Tokyo. These trains included transverse seating in some cars and were also equipped with toilets. Production continued into 2006 with trains delivered for use on the Tokaido Main Line south from Tokyo. From 2004 onward, two bilevel Green cars were inserted into all E231-1000 series ten-car sets.