The propulsion systems comprise totally enclosed permanent magnet synchronous motors (PMSM) and four-in-one variable voltage, variable frequency traction inverters. The PMSM delivers energy efficiency of 97% and the enclosed design eliminates the need for cleaning during its service life, minimising maintenance.

The four-in-one VVVF inverter system features inverter circuits for each cooling unit and is smaller and lighter than existing systems. Toshiba says the system, which integrates two four-in-one inverter units with inverter circuits, cuts power consumption by 30-50% compared with its previous system through its ability to drive up to eight PMSMs. In addition the regenerative braking control system is also able to harvest more energy than previous models, boosting the train's overall energy efficiency.

Seibu Railway is one of Tokyo's largest private rail operators, and serves western Tokyo from Shinjuku station, and northern Tokyo and Saitama from Ikebukuro station.

Seibu Railway

The series 40,000 trains have been nicknamed "Smile Train."