The is a metro electric multiple unit (EMU) train type operated by the Yokohama City Transportation Bureau on the Yokohama Municipal Subway Blue Line in Japan since 2022.
The sets have four powered cars and two leading trailer cars, and are formed as follows.
Longitudinal bucket seating is used throughout.
Construction is of stainless steel. Cars are long (leading cars are longer), wide, and approximately tall. The trains use a VVVF traction control system that allows for full regenerative braking. The trains have a maximum design speed of but are limited to during operation.
On 13 December 2021, the Yokohama Municipal Subway announced that new trainsets would be purchased for the Blue Line, replacing the oldest 3000A series trainsets dating back to 1992.
The order was originally made in 2018 for a new batch of 3000V series trainsets but that plan was abandoned in favour of newer 4000 series cars.
, five trainsets (30 vehicles) are to be commissioned in 2022 while the remaining three sets (18 vehicles) will enter service in 2023.
The first trainset entered service on 2 May 2022.
To replace the rest of the 3000S series series, eight sets of the second batch of 4000 series cars are scheduled to be introduced between 2027 and 2030. These cars will be manufactured by J-TREC.