E231系 中央・総武線を中心に掲載しています。
In 1999, EMU 209-950 was built to test TIMS information transmission and IGBT inverter technology, and was later reclassified as E231-0. After two years of testing, a total of 30 trainsets (300 cars) were delivered for Chuo-Sobu local services from Mitaka to Chiba. One trailer car has six doors per side.