Seibu 2000 series

As of 12 December 2022^[update], the fleet consists of 290 vehicles formed as two-car, four-car, six-car, and eight-car sets, and is based at Kotesashi, Musashigaoka, Minami-Iriso, Tamagawa-Josui depots for use on the Seibu Shinjuku Line and Seibu Ikebukuro Line.

Seating consists of longitudinal bench seating throughout. Priority seats are provided at the end of each car.

• Interior view
• Priority seating
• Wheelchair space

• Early-style interior in 2014
• Mid-style interior in 2014
• Late-style interior in 2014

For renewed type 2000 series interior, see renewal section.

The 2000 series trains were introduced on local train services on the Seibu Shinjuku Line in 1977, featuring four pairs of sliding doors on each side to speed up boarding and alighting at stations, and they were initially formed as six-car sets.

The last early-model 2000 series eight-car set, 2007, was withdrawn in April 2022. Train set 2055 (a first generation six-car set) was manufactured in January 1989 and was set with a vehicle number of -10 in September 1991 and became 2045 in order to avoid number depletion due to the increase of eight-car train sets. A new eight-car set, 2055 (second generation), was manufactured from December 1992 to March 1993. This second-generation set 2055 was manufactured after set 2097, and this is the final train set of the new 2000 series.

In 2025, multiple two-car sets were transferred to Ohmi Railway, a wholly owned subsidiary of Seibu. The first of these sets began service on 18 November of that year.

From new 2000 series train sets that were more than 20 years after they were made, a renewal and some fixing of the parts were started. The first renewal was made to the train set 2047 (6 cars) which were renewed from December 2007 to March 2008. The renewal contents include:

• Changing the pantographs to single-arm type.
• Replacing the original destination displays with full-color LED displays.
• Adding a number plate at the cab front to indicate the set number. (example: 2077)
• On the side of the train, the part that shows the number of the train set was changed to a plate and windows on the door pockets were removed.
• To stop passengers from falling onto the train tracks, in some of the train sets, they placed a speaker to warn passengers.
• Exchanging the horn.

• Train with added number plate at the cab front
• Intermediate car with door pocket windows removed and added plate number
• For comparison: unrefurbished intermediate car with door pocket windows and without numbering plate

• Changing the floor to grey rubber and in the areas close to the doors, the color of the floor became yellow.
• Changing the seat moquetteto blue for regular seats and to a purple-fire resistant material for priority seats. Similar to Seibu 30000 series, the S-spring is used for the cushion material. The curtains of the windows were also replaced. Also, the spaces that had the extra windows removed became advertisement spaces.
• Changing the material of the roof's air conditioning part to hard plastic from metal.
• Adding a door chime, changing the door engine and including an LED passenger information display above the train doors.
• Adding a wheelchair space and some other parts.

• Interior view of a New 2000 series train after renewal
• Priority seating
• Newly established wheelchair space
• LED passenger information display

Sets are formed as two-car, four-car, six-car, and eight-car sets, as shown below.

The "Mc" cars each have two pantographs.

• A two-car set

The "M3" cars each have two lozenge-type pantographs.

• A four-car set

The "M1" and "M5" cars each have two single-arm pantographs.

• A 2000 series six-car set
• A New 2000 series six-car set

The "M1", "M3", and "M5" cars each have one pantograph.

※Sets 2001 to 2007 are:

• A 2000 series eight-car set. This set first consisted of six cars. Two intermediate cars were added.
• A new 2000 series eight-car set

From 6 April 2015, set 2075 had a wrapping depicting the character Koro-sensei from Assassination Classroom. On June, the wrapping design was changed. The wrapping was removed in late June.

From 28 December 2015, a different wrapping also based on Assassination Classroom was put on set 2069. The wrapping was removed in late February 2016.

From 18 March 2017, set 2007 had a wrapping depicting Japan and Taiwan's tourist spots. From 26 February 2018, the design was renewed, and it started running as "Seibu Railway x LAIMO" wrapping train second edition. Originally, the train was supposed to have wrappings on it until December 2019, but its wrapping was removed in April 2019.

On 6000 series set 6158, there was also a similar wrapping, but this train's wrapping period was extended, and it had wrappings until late February 2021.

From 24 January 2023, set 2069's color was changed and it was run as "Seibu Railway 110th Anniversary Train". It commemorates the 110th anniversary of Seibu Railway's founding, and it is painted imitating the "Deha 5560 type", a vehicle representing Musashino Railway, the predecessor of the Seibu railway. At the end of March, the Musashino railway coat of arms and car name imitation mark of the Musashino Railway era were affixed to the sides of both leading cars.

In this section, to prevent confusion, "old 2000 series" is used to classify 2000 series, and "new 2000 series" will be to classify new 2000 series, and "2000 series" is used for both 2000 series and new 2000 series.

Because of the Tanashi accident [ja] that happened in 1986, sets 2017, 2023, 2407 and 2415 were damaged, and cars 2017, 2117, 2118, 2217, 2227, 2024, 2415 and 2416 (8 cars in tatal) were withdrawn. Set 2017 and 2023 had 6 undamaged cars in total, and by changing cars 2218 to 2224 as well as cars 2018 to 2024, set 2023 was made.

Sets 2023, 2009, 2013, 2029 and 2025 (30 cars in total) were withdrawn.

Sets 2097, 2011, 2005, 2015 and 2019 (34 cars in total) were withdrawn.

Set 2097 was the first new 2000 series and the first eight-car train set to be withdrawn.

Set 2021 (6 cars in total)

Sets 2003, 2407, 2001, 2411, 2063, 2401, 2519 and 2521 (38 cars in total) were withdrawn.

Set 2407 was the first two-car train set to be withdrawn.

Set 2063 was the second new 2000 series to be withdrawn, and from this point, the withdrawal of new 2000 series had become full-fledged.

Sets 2007, 2059, 2503, 2413, 2501, 2033, 2027, 2405, 2505, 2057, 2061, 2515, 2403 and 2511 (70 cars in total) were withdrawn. As part of Seibu group's plan to overcome the COVID-19, an abnormal amount^{[clarification needed]} of train sets were withdrawn.

As set 2007 was the old 2000 series' last eight-car train set, and from 29 March, set 2007 had some headmarks and special stickers on the train, and also had 2 tour runs before withdrawal, including a last-run tour.

Train set 2033 was 2000 series' first renewed train set to be withdrawn. Because of the withdrawal of train set 2027, there are no more 3-color-LED trains in the 2000 series; and only one 3-color-LED trainset in Seibu railways' fleet remains. Since train set 2403 was withdrawn, trains using roller-blind displays in the old 2000 series was gone.

In October, set 2031 was withdrawn. As set 2031 was old 2000 series' last six-car train set, 3 events were held, including a last-run tour as with train set 2007 on 5 October. With that, only three two-car sets (six cars in total) remain in the old 2000 series fleet.

The cab end of former car Tc 2098 is preserved inside the Maruzen Ikebukuro bookshop in Toshima, Tokyo. Built in June 1992 at Seibu Railway's Tokorozawa factory, it was withdrawn in September 2016, and moved to the ground floor of the Maruzen Ikebukuro bookshop building in March 2017, while still under construction.

• Saito, Yoshihiro (October 2008), "西武鉄道 新2000系バリアフリー化工事", Railway Pictorial (in Japanese), vol. 810
• "西武鉄道ニュース". Railway Pictorial (in Japanese). Vol. 914. February 2016. ASIN B007QTSLNQ.
• "西武鉄道の世界—身近な鉄路の"本格派"雑学". トラベルムック (in Japanese). Kotsu Shimbunsha. 5 October 2015. ISBN 978-4330608150.