Seibu 40000 series
The Seibu 40000 series is a commuter electric multiple unit train type operated by the private railway operator Seibu Railway in Japan since March 2017. A total of eight ten-car trainsets are to be built by Kawasaki Heavy Industries in Kobe from 2016, with the first trains entering service on 25 March 2017.
Design
The new 40000 series trains were built by Kawasaki Heavy Industries in Kobe from January 2016, with deliveries scheduled to continue from fiscal 2016 to 2019. This is the first time that trains for Seibu Railway have been built by this manufacturer.The new trains are designed as an evolution of the 30000 series "Smile Train" concept, and are intended to be passenger-friendly. The trains use PMSM.
Operations
The 40000 series trains operate on Seibu Ikebukuro Line, Seibu Shinjuku Line, and Seibu Haijima Line services. Some trainsets operate on reserved-seat supplementary-fare S-Train services between the Seibu Ikebukuro Line and Tokyo Metro Yurakucho Line on weekdays and between the Seibu Chichibu Line and Minato Mirai Line at weekends since 25 March 2017.Formation
The 40000 series EMUs are ten-car sets formed as follows, with five motored cars and five non-powered trailer cars, and car 1 at the Hanno end.| Car No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Designation | Tc1 | M1 | M2 | T1 | M3 | T2 | T3 | M5 | M6 | Tc2 |
| Numbering | 4010x | 4020x | 4030x | 4040x | 4050x | 4060x | 4070x | 4080x | 4090x | 4000x |
| Weight | 29.5 | 36.9 | 35.0 | 28.2 | 34.6 | 26.7 | 27.2 | 37.0 | 34.8 | 28.6 |
| Capacity longitudinal config. | 124/38 | 132/45 | 132/48 | 126/42 | 132/48 | 132/48 | 132/48 | 132/48 | 132/45 | 125/30 |
| Capacity transverse config. | 119/38 | 127/45 | 127/48 | 121/42 | 127/48 | 127/48 | 127/48 | 127/48 | 127/45 | 121/30 |
Cars 2, 5, and 8 each have one single-arm pantograph. Car 4 has a universal access toilet.
Interior
Passenger accommodation consists of longitudinal bench seating, but some trainsets feature rotating pairs of seats that can be arranged in either longitudinal or transverse arrangements. LED lighting is used in the interiors, and pairs of LCD passenger information screens are provided both above the doorways and suspended form the ceilings. A "Partner zone" area is provided at the end of car 10 with perch seats and space for wheelchairs and large luggage. This area also has larger windows. "Plasmacluster" air-purification technology is used for the first time on Seibu Railway trains.History
Details of the new trains were officially announced in August 2015. The first trainset, 40101, was delivered from the Kawasaki Heavy Industries factory in Kobe to Seibu's Kotesashi Depot in September 2016.The first sets entered revenue service on S-Train services on 25 March 2017.
From spring 2018, 40000 series trains are scheduled to be used on new Haijima Liner limited-stop supplementary-fare commuter services operating from to on weekday evenings.
Build histories
The manufacturers and delivery dates for the fleet are as shown below.| Set No. | Manufacturer | Date delivered |
| 40101 | Kawasaki Heavy Industries | 10 January 2017 |
| 40102 | Kawasaki Heavy Industries | 11 January 2017 |
| 40103 | Kawasaki Heavy Industries | October 2017 |
| 40104 | Kawasaki Heavy Industries | November 2017 |
| 40105 | Kawasaki Heavy Industries | January 2018 |
| 40106 | Kawasaki Heavy Industries | February 2018 |
| 40107 | ||
| 40108 |
;Notes: