The 2000 series is a type of commuter train with four sets of doors per carriage. It is the first four-door commuter train that Seibu developed, and completely new traction and braking systems with regenerative feature were adopted. There are two, four, six and eight-carriage units, and they can be formed of up to ten coaches. They were initially introduced to Seibu the Shinjuku Line, where stopping services often caused minor delays at peak times due to congestion. They were also used on the Ikebukuro Line as well in 1990-2025.
The 2000 series is classified into two groups: 2000 series in a narrow sense and so-called N2000 series. They look different but share the same traction and braking systems, and thus they can be coupled with each other.
The 2000 series trains were introduced in 1977-88. Some of their parts, such as doors, windows between doors and large fans for ventilation, were very similar to those of commuter trains that Japanese National Railways introduced in the 1970s. Gears, motors and traction were almost identical to those of Tokyu 8500 series. They were mostly used on Seibu the Shinjuku Line (including relevant branch lines), but some ran the Ikebukuro Line sporadically. Each unit was formed of two or six coaches (there were also eight-car units in the past).
They were gradually replaced with 30000 series and 40000 series by 2025. Two two-car units were transferred to Ohmi Railway in Shiga Prefecture, where they are called 200 series.
The N2000 series trains were introduced in 1988-92. 314 carriages in total were introduced, making them the flagship of Seibu. They can be further classified into several groups, but this article does not describe them in detail. They have been used on both Seibu Shinjuku and the Ikebukuro Lines as well as other branch lines. Each unit consists of two, four, six or eight coaches, and many of them have been refurbished by the late-2000s.
The N2000 series and 9000 series share the same body and exterior design, but their traction and motors are completely different. Those on the Ikebukuro Line were either demolished or reallocated to the Shinjuku Line by 2025.
Ohmi Railway in Shiga Prefecture acquired a two-car unit in 2024 and renamed 200 series Dr Gachakon, to replace even older trains. The 200 series can also be used as measurement trains.
In 2023, an eight-car unit was repainted brown like Seibu trains of old days (to be specific, Musashino Railway 5560 series which was operational in 1928-58), in commemoration of the 110th anniversary of the company.
Current Operations & Future Prospects
The N2000 series are used on the Seibu the Shinjuku Line and relevant branch lines, where it is hard not to see any of them. Since the N2000 series is not environmentally friendly, the company is going to gradually replace them with the 40000 series and other "second-hand" trains from Odakyu and Tokyu by early-2031.
The 200 series of Ohmi Railway entered into service in October 2025.
