E231 series

E231 series
A516 in July 2023
Technical specifications
Manufacturer(s)	JR East's Niitsu Works, Kawasaki Heavy Industries, Tokyu Car Corporation
Designer(s)	Kenji Ekuan
Type of locomotive	Electric multiple unit
Constructed	1998 – 2011
Number built	2,736 cars
Dimensions	787 in (20,000 mm) × 116 in (2,950 mm) × 157 in (3,980 mm)
Gauge	3 ft 6 in (1,067 mm)
Power supply	Pantograph
Electric system(s)	1,500 V DC
Traction system	Variable frequency (IGBT, 2-level IGBT)
Service information
In service	13 March 2000 – Present
Formation	4, 5, 8, 10 or 11 cars per set
Number in service	2,476 cars (+48 converted to E235 series cars)
Fleet numbers	B1 – B4, B7 – B21, B23 – B42, B57, B80 – B82, MaTo101 – MaTo117, MaTo121 – MaTo139, MU1 – MU3, MU22, MU31, A501 – A552, K1 – K7, U2 – U118, U501 – U541, U584 – U591, K1 – K42, S1 – S34, Hae41 – Hae46, Hae101 – Hae119, Hae121 – Hae139
Refurbished	2014 – Present
Scrapped	2010 – Present
Preservation information
Preserved	0
Number scrapped	212 cars

The E231 series is a Japanese commuter electric multiple unit operated in a number of different forms by the East Japan Railway Company since March 2000. It is one of a few main types of rolling stock used on urban commuter services on JR East, with another being the E233 sets, as well as some long-distance services. It is most famously known as the main rolling stock on the Yamanote Line, a major loop line in the Tokyo region, from 2000 to 2020.

History

The E231 series was designed in 1998 to replace various city commuter trains like 103, 201, 205 and 301 series sets and outer-suburban commuter trains like the 113 and 115 series. The first set entered service on 13 March 2000.

A total of 2,736 cars were built, with the majority still in service based at various depots around Japan. Occasionally, six-doored cars are inserted into the sets to allow for more passengers to board the train during busy periods. These were originally used on the Yamanote Line, but with the addition of platform screen doors on most of the stations to standardize door spacing, these six-doored cars were removed and replaced by new cars with irregularly-spaced doors to fulfill the same purpose.

Of note is that the first set delivered, E231-900 series set B901, was actually originally classified as a 209-950 series set; that set entered service on 27 March 1999. The set was reclassified as E231-900 series set B901 in June 2000 with the manufacture of the full-production cars. B901 was removed from service on the Chūō-Sōbu Line on 9 July 2020 and subsequently transferred to the Musashino Line, reformed as an 8-car set and renumbered MU1; the two cars removed from the set were scrapped in December 2020.

The sets were entirely phased out of service on the Yamanote Line on 20 January 2020, with YaTe506 (now A506) carrying a special headmark.

Design

The E231 series uses a modern design with an unpainted stainless steel body very much like most JR East commuter trains; the sets are based on the 209 series so some design language does carry over. Each set has a different color scheme to indicate which area the sets serve. The sets have a wide variety of different body styles based on the different variations of the set. The basic designs of the sets was designed by industrial designer Kenji Ekuan.

Variations

Livery variations

Operating area	Front end	Body side
Chūō-Sōbu Line
Jōban Line/Narita Line
Musashino Line/Keiyō Line
Yamanote Line
Chūō-Sōbu Line/Tokyo Metro Tozai Line through-running
Tōkaidō Main Line/Utsunomiya Line/Takasaki Line/Shōnan-Shinjuku Line
Kawagoe Line/Hachikō Line

Cab design variations

There are four cab design variations of the E231 series, with each cab design variation being used on the role the sets are used on.

Mid-distance commuter set B3 in May 2017

Prototype mid-distance commuter set B901 (now MU1) in January 2015

Outer-suburban set S20 in February 2017

Narrow-body set K5 in November 2010

City commuter set A507 in July 2017

City commuter set YaTe525 (now A525) in February 2018

Specifications

Construction is of stainless steel. Cars are 20 meters long, 2.95 meters wide and 3.98 meters high. Traction motors are powered by three-level insulated gate bipolar transistors supplied by Mitsubishi or two-level IGBT drives supplied by Hitachi and Mitsubishi which are only used on various refurbished sets.

The Mitsubishi drives fitted on the E231-0, E231-500, E231-800 and E231-900 series sets make a distinctive, wind-like noise when the train accelerates from idle; the later-build E231-1000 series sets use early-spec Hitachi drives which make a shrill noise which later dies down but rises in pitch again; refurbished sets use two-level Mitsubishi drives which make a hissing noise or later-spec two-level Hitachi drives which make a high-pitched wooshing noise.

There are even other variations of the two-level Hitachi drives which do not have the abrupt pitch shifts.

The E231 series sets are one of a few sets which are the blueprints for successive trains developed by JR East; others include the E233 and 209 series sets.

References

• Wikipedia.org