E231 series
A Chūō–Sōbu Line E231-0 series train in December 2022
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	1998–2006 2010–2011 (SaHa E231-600 & SaHa E231-4600 carriages)
Entered service	13 March 2000
Refurbished	2014–
Scrapped	2010–
Number built	2,736 vehicles
Number in service	2,476 vehicles (+48 vehicles converted to E235 series)
Number scrapped	212 vehicles
Successor	E235 series (Yamanote Line)
Formation	4/5/8/10 cars per trainset (Previously also 11)
Operators	JR East
Depots	Kawagoe, Keiyō, Kōzu, Matsudo, Mitaka, Oyama
Lines served	(See below)
Specifications
Car body construction	Stainless steel
Car length	20,000 mm (65 ft 7 in)[1]
Width	2,950 mm (9 ft 8 in)[1]
Doors	4 pairs per side (previously also 6 pairs per side) 2 doors per side (Green cars)
Maximum speed	120 km/h (75 mph)[1]
Traction system	IGBT-VVVF
Acceleration	2.5, 3, or 3.3 km/(h⋅s) (1.6, 1.9, or 2.1 mph/s)
Deceleration	4 km/(h⋅s) (2.5 mph/s) (service) 4.5 km/(h⋅s) (2.8 mph/s) (emergency)
HVAC	AU725/AU726
Electric system(s)	1,500 V DC overhead
Current collector(s)	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 (for E231-1000 series only)
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 (9 ft 8 in) compared to the 2,800 mm (9 ft 2 in) for earlier commuter trains), and the prototype train built in 1998 for trials on the Chūō–Sōbu Line was actually classified 209-950 series, later becoming E231-900 series. Full-production E231-0 series trains were subsequently introduced on the Chūō–Sōbu Line (10-car sets) and Jōban 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 (9 ft 2 in) wide bodies and end doors for use on Tokyo Metro Tozai 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 Tōkaidō Main Line south from Tokyo. From 2004 onward, two bilevel Green cars were inserted into all E231-1000 series ten-car sets.

• / / E231-0 series: 5-car, 8-car, and 10-car sets used on the Chūō–Sōbu Line, Jōban Line, Narita Line, Musashino Line, and Keiyō Line
• E231-500 series: 10-car sets used on the Chūō–Sōbu Line
• E231-800 series: 10-car sets used on Chūō–Sōbu Line and Tokyo Metro Tozai Line interrunning services
• E231-900 series: 8-car set used on the Musashino Line and Keiyō Line
• E231-1000 series: 5-car and 10-car suburban sets used on the Tōkaidō Main Line, Utsunomiya Line, and Takasaki Line, and on Ueno–Tokyo Line and Shōnan–Shinjuku Line through services
• E231-3000 series: 4-car sets converted from former E231-0 series sets for use on the Kawagoe Line and Hachikō Line

• E231-500 series: 11-car sets used on the Yamanote Line from 21 April 2002 until 20 January 2020
• E231-900 series: 10-car set used on the Chūō–Sōbu Line from December 1998 until 25 February 2020 (designated as 209-950 series until June 2000)

E231-0 series
A Jōban Line 10+5 car set in March 2021
Replaced	103 series, 103-1000 series, 201 series, 205 series, 205-5000 series
Constructed	2000–2006
Entered service	13 March 2000
Refurbished	2014–2020
Number built	725 vehicles
Number in service	599 vehicles (76 sets) (+24 vehicles converted to E231-3000 series)
Number scrapped	102 vehicles
Formation	5/8/10 cars per trainset
Operators	JR East
Depots	Keiyō, Matsudo, Mitaka Previously: Narashino
Lines served	JB Chūō–Sōbu Line JJ Jōban Line JE Keiyō Line JM Musashino Line ■ Narita Line (Abiko Branch) JT Tōkaidō Line ■ Ueno–Tokyo Line
Specifications
Car body construction	Stainless steel
Width	2.95 m (9 ft 8 in)
Doors	4 pairs per side (previously also 6 pairs per side)
Traction system	Variable frequency (Mitsubishi IGBT-VVVF)
Traction motors	MT73
Power output	95kW Per Motor
Transmission	Gear Ratio: 14:99=1:7.07
Electric system(s)	1,500 V DC overhead catenary
Current collector(s)	PS33B pantograph
Track gauge	1,067 mm (3 ft 6 in)

The first full-production E231-0 series trains were introduced on the Chūō–Sōbu Line between February 2000 and November 2001, with 21 ten-car sets (101–121) based at Narashino Depot in Chiba^[2] and 21 ten-car sets (20–25, 28–42) based at Mitaka Depot in Tokyo.^[3] They replaced older 103, 201, and 205 series trains. One more ten-car set (57) was delivered to Mitaka Depot in November 2002. In December 2003, all Narashino sets were transferred to Mitaka Depot and renumbered 1–19, 26, and 27. Between October and November 2006, three more sets (80–82) were built to replace three 209-500 series sets transferred to the Keihin–Tōhoku—Negishi Line, creating a total fleet of 46 trains. The Chūō–Sōbu Line sets each contained a six-door car.^[4]

New built E231-0 series sets were also delivered to Matsudo Depot between November 2001 and February 2005 for use on Jōban Line services between Ueno and Toride, and also Narita Line services to Narita, replacing the earlier 103 series fleet. A total of 17 ten-car sets (101–117) and 19 five-car sets (121–139) were built.^[5]

From December 2009 to November 2011, set 27 was temporarily transferred to Tokyo General Rolling Stock Center and used to deliver new SaHa E231-600 and SaHa E231-4600 trailer cars for the Yamanote Line. In 2012, a "B" suffix was added to all Chūō–Sōbu Line sets (B1–B42, B57, and B80–B82).

Between 2015 and 2020, all E231-0 series sets underwent a mid-life refurbishment with new equipment. In addition, with the transfer of former Yamanote Line E231-500 series sets to the Chūō–Sōbu Line and to prepare for the installation of platform doors, 40 trains were transferred from the Chūō–Sōbu Line to other lines, while six trains were reformed and remain on the Chūō–Sōbu Line with all six-door cars replaced with excess four-door cars from the other 40 sets.^[6]

In late 2014 and early 2015, two Chūō–Sōbu Line sets (B20 and B21, with six-door cars substituted by two trailer cars from B22) were transferred to the Jōban Line (and renumbered 118 and 119)^[4] for the extension of the Jōban Line services to Shinagawa Station with the opening of the Ueno–Tokyo Line. This brought the total number of Jōban Line sets to 38 (19 five-car and 19 ten-car sets), all of which were refurbished between 2015 and 2020.

From October 2017 to September 2020, 32 Chūō–Sōbu Line sets were refurbished, shortened to eight cars, and transferred to the Musashino Line (and renumbered MU2–MU21, MU31–MU39, and MU41–MU43) to replace older 205 series and 205-5000 series sets; the first set (MU2) entered service in November 2017.^[7]

From November 2017 to October 2019, six Chūō–Sōbu Line sets were refurbished, shortened to four cars, redesignated as E231-3000 series, and transferred to the Hachikō Line and Kawagoe Line.

The first reformed E231-0 series Chūō–Sōbu Line train (with 6 motored cars and no six-door car), numbered set B11 and composed of 8 cars of former set B11 and 2 cars of former set B5, completed refurbishment on 24 April 2018 and reentered into service on 21 May 2018.^[8] A total of six reformed ten-car trains remain on the Chūō–Sōbu Line. The last non-reformed trains (with 4 motored cars and a six-door car), sets B80 and B82, were removed from service after 13 March 2020.^[9]

Between 17 August^[10] and 7 October 2020,^[11] Jōban Line set 118 was shortened to 8 cars and modified for use on the Musashino Line at Nagano depot. It was renumbered MU22 and reentered service on 12 October.^[12]

• Chūō–Sōbu Line
• Jōban Line (Rapid) (Toride – Ueno), Ueno–Tokyo Line, Tōkaidō Line (Tokyo – Shinagawa) and Narita Line (Abiko – Narita)
• Musashino Line, Keiyō Line (also Musashino and Shimōsa)

As of 19 March 2020, six ten-car sets (B10–B12, B14, B26, B27) are based at Mitaka depot in Tokyo and formed as shown below with six motored ("M") cars and four non-powered trailer ("T") cars.^[4]

• Cars 2, 5, and 8 each have one PS33B single-arm pantograph.
• Cars 1 and 10 have a wheelchair space.
• Car 4 is designated as a mildly air-conditioned car.

As of 17 August 2020, 18 ten-car sets (101–117, 119) are based at Matsudo depot in Chiba Prefecture and formed as shown below with four motored ("M") cars and six non-powered trailer ("T") cars.^[13]

• Cars 3 and 8 each have one PS33B single-arm pantograph.^[4]
• Cars 1 and 10 have a wheelchair space.^[4]
• Car 8 is designated as a mildly air-conditioned car.^[4]

As of 1 October 2018, 19 five-car sets (121–139) are based at Matsudo depot in Chiba Prefecture and formed as shown below with two motored ("M") cars and three non-powered trailer ("T") cars.^[4]

• Car 13 has one PS33B single-arm pantograph.^[4]
• Cars 11 and 15 have a wheelchair space.^[4]
• Car 14 is designated as a mildly air-conditioned car.^[4]

As of 12 October 2020, 33 eight-car sets (MU2–MU22, MU31–MU39, MU41–MU43) are based at Keiyō Depot and formed as shown below with four motored ("M") cars and four non-powered trailer ("T") cars.^[14]

• Cars 2 and 6 each have one PS33B single-arm pantograph.^[4]
• Cars 1 and 8 have a wheelchair space.^[4]
• Car 4 is designated as a mildly air-conditioned car.^[4]

• Cars 3 and 8 each had one PS33B single-arm pantograph.^[4]
• Car 5 had six pairs of doors per side.^[4]
• Cars 1 and 10 had a wheelchair space.^[4]
• Car 4 was designated as a mildly air-conditioned car.^[4]

• 
  A Chūō–Sōbu Line 10-car E231-0 series set in August 2022
• 
  A Jōban Line 10+5-car E231-0 series formation in July 2008
• 
  Musashino Line 8-car E231-0 series set MU19 in January 2023

• 
  Interior view of KuHa E231-71 car
• 
  Priority seating of Moha E230-128 car
• 
  Wheelchair and stroller space of Kuha E230-71 car
• 
  Passenger information screen

In April 2021, to commemorate the 120th anniversary of the Abiko Branch Line, JR East recolored set 139 into Sōbu/Yokosuka Line blue and cream stripes. Initially, only the cab ends received the commemorative stripes; however, these stripes were later extended to the rest of the train's body.^[15] The trainset was painted back into its original livery in late October.^{[citation needed]}

• 
  Set 139 with the cab front in Sōbu/Yokosuka Line color, April 2021
• 
  Set 139 in complete Sōbu/Yokosuka Line livery in May 2021

E231-500 series
Chūō–Sōbu Line 10-car E231-500 series set A545 in March 2021
Replaced	205 series, 209-500 series, E231-0 series
Constructed	2002–2005, 2010–2011 (SaHa E231-600, SaHa E231-4600)
Entered service	21 April 2002
Refurbished	2014–2020
Scrapped	2010–2011 (SaHa E230-500 x104) 2020 (SaHa E231-4600 x4)
Number built	676 vehicles
Number in service	520 vehicles (52 sets) (+48 vehicles converted to E235 series)
Number scrapped	108 vehicles
Successor	E235-0 series (Yamanote Line)
Formation	10 (previously 11) cars per trainset
Fleet numbers	A501–A552 Previously: 501-552
Operators	JR East
Depots	Mitaka Previously: Tokyo
Lines served	JB Chūō–Sōbu Line Previously: JY Yamanote Line
Specifications
Car body construction	Stainless steel
Width	2,950 mm (9 ft 8 in)
Doors	4 pairs per side (previously also 6 pairs per side)
Electric system(s)	1,500 V DC overhead catenary
Current collector(s)	PS33B pantograph
Track gauge	1,067 mm (3 ft 6 in)

A fleet of 52 11-car E231-500 series was delivered from January 2002 to April 2005 for use on Yamanote Line services, replacing the earlier 205 series fleet. The first trains entered service on 21 April 2002. These trains include digital automatic train control (D-ATC), and feature pairs of LCD passenger information screens above each door internally. These screens also show advertisements. Each 11-car set originally contained two six-door SaHa E230 trailer cars (cars 7 and 10)^[5] with six pairs of doors per side and bench seats that were folded up until 10 a.m. on weekdays to provide standing room only during the morning peak. From 22 February 2010, the seats were able to be used during the morning peak.^[16]

To standardize door spacing ahead of the introduction of platform doors on all Yamanote Line stations by 2017, the two six-door cars in each set were subsequently replaced by a new build of four-door trailer cars between February 2010 and August 2011,^[16] the first of which were delivered from JR East's Niitsu factory on 1 February 2010.^[17]

The new SaHa E231-600 cars (new car 7) incorporated some elements from the newer E233 series (most notably seats and handrails).^[18] The new SaHa E231-4600 cars (new car 10) were built almost fully to E233 series standards;^[19] they also have an irregular door spacing corresponding to the driving cars of Keihin–Tōhoku Line E233-1000 series sets, which occasionally have to share the same platforms during engineering work. This results in interior seating arranged 3-7-7-5-4, instead of the normal 3-7-7-7-3 arrangement.^[20]

In October 2014, former Yamanote Line set 520 was released from overhaul as a ten-car set, numbered A520, allocated to Mitaka Depot, and finished in the yellow Chūō–Sōbu Line livery.^[21] It entered revenue service on the Chūō–Sōbu Line from 1 December 2014.^[22] A second set, former Yamanote Line set 540 was converted to a ten-car set for use on the Chūō–Sōbu Line in May 2016, renumbered A540.^[23] Between 2017 and 2020, the remaining sets were transferred to the Chūō–Sōbu Line as the E235 series replaced them on the Yamanote Line.^[24] The SaHa E231-4600 cars were removed as the Chūō–Sōbu Line uses 10-car trains. As a result, 48 of the 52 surplus SaHa E231-4600 cars were updated to E235 series standards (and re-numbered SaHa E235-4600) and continue to be used on the Yamanote Line, while the remaining 4 cars were scrapped.^[25] The last set of E231-500 (Set 506) on the Yamanote Line finished service in January 2020 and was converted for service on the Chūō–Sōbu Line as set A506.^[26]

• Chūō–Sōbu Line

• Yamanote Line

As of 3 March 2020, 52 ten-car sets (A501-A552) are based at Mitaka depot in Tokyo and formed as shown below with six motored ("M") cars and four non-powered trailer ("T") cars.^[4]

• Cars 2, 5, and 8 each have one PS33B single-arm pantograph.^[4]
• Cars 1 and 10 have a wheelchair space.^[4]
• Car 4 is designated as a mildly air-conditioned car.^[4]

• Cars 3, 6, and 9 each had one PS33B single-arm pantograph.^[4]
• Cars 1 and 11 had a wheelchair space.^[4]
• Car 4 was designated as a mildly air-conditioned car.^[4]

• Cars 3, 6, and 9 each had one PS33B single-arm pantograph.
• Cars 7 and 10 was a "six door car" meaning it had six pairs of doors per side.
• Cars 1 and 11 had a wheelchair space.
• Car 4 was designated as a mildly air-conditioned car.

• 
  SaHa E230-500 6-door car as car No. 10 in June 2010
• 
  Replacement SaHa E231-4600 4-door car as car No. 10 in June 2010
• 
  Replacement SaHa E231-600 4-door car as car No. 7 in March 2010

• 
  Interior view of SaHa E231-500 car
• 
  Interior view of SaHa E230-500 car with seats folded up for the rush hour
• 
  Interior view of SaHa E231-4600 car, showing E233 series derived interior, April 2010
• 
  Passenger information screen

From 7 September to 4 December 2009, E231-500 series set 502 carried an all-over brown livery to mark the 100th anniversary of the naming of Yamanote Line in collaboration with the Meiji Seika confectionery company.

From 16 January to 28 December 2013, Yamanote Line E231-500 series set 545 operated in an all-over uguisu light green livery to mark the 50th anniversary of the first appearance of 103 series EMUs in this colour scheme.^[27]

From 11 October 2014 to 31 March 2015, Yamanote Line E231-500 series set 514 operated in an all-over "red brick" livery to commemorate the 100th anniversary of the opening of Tokyo Station, which opened in 1914.^[28]

• 
  Set 502 in all-over brown livery in October 2009
• 
  Set 545 in all-over light green livery in January 2013
• 
  Set 514 in "red brick" livery in October 2014

E231-800 series
An E231-800 series set in July 2022
Replaced	103-1200 series, 301 series
Constructed	2003
Entered service	1 May 2003
Number built	70 vehicles
Number in service	70 vehicles (7 sets)
Formation	10 cars per trainset
Fleet numbers	K1–K7
Operators	JR East
Depots	Mitaka
Lines served	JB Chūō–Sōbu Line, T Tokyo Metro Tozai Line
Specifications
Car body construction	Stainless steel
Width	2,800 mm (9 ft 2 in)
Doors	4 pairs per side
Electric system(s)	1,500 V DC overhead catenary
Current collector(s)	PS33B pantograph
Safety system(s)	ATC, ATS-SN/P[29]
Track gauge	1,067 mm (3 ft 6 in)

The E231-800 series (E231系800番台) fleet consists of seven 10-car sets (K1 to K7), which are based at Mitaka Depot for use on Chūō–Sōbu Line and Tokyo Metro Tozai Line inter-running services. These sets were delivered between January and May 2003, entering service on 1 May 2003^[5][30] and replacing the ageing fleet of 103 and 301 series sets.^[29]

The design of the E231-800 series is largely similar to that of the 209-1000 series—which was also designed with subway interoperation in mind—featuring end gangways that are used for emergency egress. Furthermore, the car bodies are 2,800 millimetres (9 ft 2 in) wide,^[29] as opposed to 2,950 millimetres (9 ft 8 in) for the rest of the E231 series fleet.^[1] They also have an increased power output due to the conditions of the Tozai Line.^[29]

• Tokyo Metro Tozai Line
• Chūō–Sōbu Line (Mitaka – Nakano; Nishi-Funabashi – Tsudanuma)

As of 1 October 2018, seven ten-car sets (K1 to K7) are based at Mitaka depot in Tokyo and formed as shown below with six motored ("M") cars and four non-powered trailer ("T") cars.^[4][29]

• Cars 2, 5, and 8 each have one PS33B single-arm pantograph.^[4]
• Cars 2 and 9 have a wheelchair space.^[4]
• Car 4 is designated as a mildly air-conditioned car.^[4]

E231-900 series
Musashino Line E231-900 series in July 2020
Replaced	205 series
Constructed	1998 (as 209-950 series)
Entered service	December 1998
Refurbished	June 2000, March–July 2020
Number built	10 vehicles
Number in service	8 vehicles (1 set)
Number scrapped	2 vehicles
Formation	8 (previously 10) cars
Fleet numbers	MU1 Previously: B901
Operators	JR East
Depots	Keiyō Previously: Mitaka
Lines served	JE Keiyō Line, JM Musashino Line Previously: JB Chūō–Sōbu Line
Specifications
Car body construction	Stainless steel
Width	2,950 mm (9 ft 8 in)
Doors	4 pairs per side (previously also 6 pairs per side)
Electric system(s)	1,500 V DC overhead catenary
Current collector(s)	PS33B pantograph
Track gauge	1,067 mm (3 ft 6 in)

This was the prototype E231 series set, built jointly by Tokyu Car and JR East's Niitsu factory, and delivered in October 1998 for the Chūō–Sōbu Line, classified as 209-950 series. It was reclassified as E231-900 series in June 2000.^[4]

On 25 February 2020, it operated its last revenue service on the Chūō–Sōbu Line. The set was refurbished at Ōmiya Rolling Stock Center between 3 March^[31] and 10 July^[32] for transfer to the Musashino Line and associated through services^[32] and reentered service on 20 July.^[33]

• Musashino Line, Keiyō Line (also Musashino and Shimōsa)

• Chūō–Sōbu Line

As of 20 July 2020, one eight-car set (MU1) is based at Keiyō Depot and formed as shown below with four motored ("M") cars and four non-powered trailer ("T") cars.^[14]

• Cars 2 and 6 each have one PS33B single-arm pantograph.
• Cars 1 and 8 have a wheelchair space.
• Car 4 is designated as a mildly air-conditioned car.

• Cars 3 and 8 each had one PS33B single-arm pantograph.^[4]
• Car 5 had six pairs of doors per side.^[4]
• Cars 1 and 10 had a wheelchair space.^[4]
• Car 4 was designated as a mildly air-conditioned car.^[4]

• 
  E231-900 series on Chūō–Sōbu Line in March 2019

E231-1000 series
A E231-1000 series suburban set on a Tokaido main line service in January 2023
Replaced	113 series, 115 series
Constructed	2000–2006
Entered service	21 June 2000
Number built	1255 vehicles
Number in service	1255 vehicles (160 sets)
Formation	5/10 cars per trainset
Operators	JR East
Depots	Kōzu, Oyama
Lines served	JU Takasaki Line JU Utsunomiya Line JT Tōkaidō Main Line JT Ito Line JS Shōnan–Shinjuku Line JO Yokosuka Line ■ Joetsu Line ■ Ryōmō Line
Specifications
Car body construction	Stainless steel
Width	2,950 mm (9 ft 8 in)
Doors	4 pairs per side 2 doors per side (Green cars)
Electric system(s)	1,500 V DC overhead catenary
Current collector(s)	PS33B pantograph
Multiple working	E233-3000 series
Track gauge	1,067 mm (3 ft 6 in)

These trains are designed for longer-distance suburban services, and include toilets, transverse seating bays (in some cars only), and bilevel Green cars (10-car sets only). The Ito Line and Joetsu Line mainly use 5-car sets, while the Shōnan–Shinjuku Line, Ueno–Tokyo Line, Takasaki Line, Tōkaidō Main Line, Utsunomiya Line use 10- or 10+5-car sets.

Ten- and five-car suburban sets based at Oyama and Kōzu depots for use on the following lines.

• Takasaki Line (Ueno – Takasaki) and Joetsu Line (Takasaki – Shin-Maebashi) and Ryōmō Line (Shin-Maebashi – Maebashi)
• Utsunomiya Line (Ueno – Kuroiso)
• Tōkaidō Main Line (Tokyo – Atami / Numazu)
  • Itō Line (Atami – Itō, through services from Tōkaidō Main Line)
• Ueno–Tokyo Line (Ueno – Tokyo)
  • Takasaki Line (Ueno – Takasaki), Joetsu Line (Takasaki – Shin-Maebashi) and Ryōmō Line (Shin-Maebashi – Maebashi)
  • Utsunomiya Line (Ueno – Kuroiso)
  • Tōkaidō Main Line (Tokyo – Atami / Numazu) and Itō Line (Atami to Itō)
• Shōnan–Shinjuku Line (Ōfuna – Ōmiya )
  • Yokosuka Line (Zushi – Ōfuna) and Utsunomiya Line (Ōmiya – Utsunomiya)
  • Tōkaidō Main Line (Ōfuna – Odawara), Takasaki Line (Ōmiya – Takasaki), Joetsu Line (Takasaki – Shin-Maebashi) and Ryōmō Line (Shin-Maebashi – Maebashi)

As of 1 October 2018, 42 ten-car sets (K-01–K-42) are based at the Kōzu depot in Kanagawa Prefecture and formed as shown below with four motored ("M") cars and six non-powered trailer ("T") cars.^[4]

• Cars 3 and 9 each have one PS33B single-arm pantograph.^[4]
• Cars 1 and 10 have a wheelchair space.^[4]
• Cars 1, 5, and 10 each have a toilet (universal design in cars 1 and 10).^[4]
• Car 8 is designated as a mildly air-conditioned car.^[4]
• Cars 4 and 5 are bilevel Green Cars.^[4]

As of 1 October 2018, 49 ten-car sets (U501–U541, U584–U591) are based at the Oyama depot in Tochigi Prefecture and formed as shown below with four motored ("M") cars and six non-powered trailer ("T") cars.^[4]

• Cars 3 and 8 each have one PS33B single-arm pantograph.^[4]
• Cars 1 and 10 have a wheelchair space.^[4]
• Cars 1, 5, and 6^[34] each have a toilet (universal design in car 1, Japanese-style in car 6).^[4]
• Car 8 is designated as a mildly air-conditioned car.^[4]
• Cars 4 and 5 are bilevel Green Cars.^[4]

As of 1 October 2018, 34 five-car sets (S-01–S-34) are based at Kōzu depot in Kanagawa Prefecture and 35 five-car sets (U2–U118) are based at Oyama depot in Tochigi Prefecture. They are formed as shown below with two motored ("M") cars and three non-powered trailer ("T") cars.^[4]

• Car 13 has one PS33B single-arm pantograph.^[4]
• Cars 11 and 15 have a wheelchair space.^[4]
• Car 11 has a universal design toilet.^[4]

• 
  Interior of car with longitudinal seating
• 
  Interior of car with transverse seating bays
• 
  Toilet
• 
  Driver's cab end
• 
  Bilevel Green Car lower deck with 2+2 seating
• 
  Bilevel Green Car upper deck with 2+2 seating

E231-3000 series
A Hachikō/Kawagoe Line four-car set in March 2018
Replaced	205-3000 series, 209-3000 series, 209-3100 series
Entered service	19 February 2018
Refurbished	2017–2019 (converted from E231-0 series) 2020–2021 (modified for driver-only operation)
Number built	24 vehicles
Number in service	24 vehicles (6 sets)
Formation	4 cars per trainset
Fleet numbers	41–46
Operators	JR East
Depots	Kawagoe
Lines served	■ Hachikō Line, Kawagoe Line
Specifications
Car body construction	Stainless steel
Width	2,950 mm (9 ft 8 in)
Doors	4 pairs per side
Electric system(s)	1,500 V DC overhead catenary
Current collector(s)	PS33B pantograph
Track gauge	1,067 mm (3 ft 6 in)

From 2017, former E231-0 series ten-car sets based at Mitaka Depot for use on Chūō–Sōbu Line services were reformed and converted to become four-car E231-3000 series sets based at Kawagoe for use on Kawagoe Line and Hachikō Line services.^[35] The first set entered revenue service on the line on 19 February 2018.^[36]

Between June 2020 and September 2021, the trains were modified for driver-only operation (wanman (ワンマン, "one man")).

• Hachikō Line (Hachiōji – Komagawa)
• Kawagoe Line (Komagawa – Kawagoe)

As of 8 October 2019, six four-car sets (41-46) are based at Kawagoe depot in Saitama and formed as shown below with two motored ("M") cars and two non-powered trailer ("T") cars.^[4]

• Car 3 has one PS33B single-arm pantograph.^[4]
• Cars 1 and 4 have a wheelchair space.^[4]

The former identities of the E231-3000 series sets are as follows.^[4]

On the evening of 5 August 2023, a Tokaido Line service led by E231-1000 series set S-14 struck a utility pole near Ofuna and lost power, reportedly due to getting caught by an overhead wire and pulling the pole.^[37] The accident resulted in four people, including the driver, sustaining minor injuries.^[38] The lead car of the set was damaged, and 1,500 passengers were evacuated after two hours. Service was restored on the morning of 6 August.

• E233 series, successor
• E331 series, experimental articulated train
• E531 series, dual-voltage derivative
• Sotetsu 10000 series, an E231 series derivative
• Toei 10-300 series, an E231 series derivative
• Tokyu 5000 series, an E231 series derivative
• SP1900 EMU, an MTR (ex-KCR) train type based on E231 series technology
• Nankai 8000 series, partly using same parts as E231

• 首都圏新系列車両 Profile: 209/E231/E233系グループの全貌 首都圏新系列車両PROFILE [Tokyo Area New-generation Rolling Stock Profile]. Japan: Ikaros Publishing. 15 April 2011. ISBN 978-4-86320-436-2.

• JR E231 series (in Japanese)
• Kawasaki Heavy Industries product information (in Japanese)
• Tokyu Car product information (in Japanese)