I am going to show you the commuter trains in Tokyo for the first time in a very long while.
The Tokyo Metro Tozai Line is one of the busiest subway routes in Tokyo. Connecting Nakano and Nishi-Funabashi (30.8km), it penetrates downtown Tokyo from west to east. The trains are directly operated onto the JR East Chuo Local Line to Mitaka and the Toyo Rapid Railway to Toyo-Katsutadai, therefore, its maximum operation length reaches 56.4 km. Thanks to the direct train operation between multiple railways, many kinds of trains are seen on the Tozai Line. I am going to show you two examples today.
The top photo is the EMU 231-800 series directly operated from the JR East Chuo Local Line. The 231-800 series was launched in 2003 to replace the old models such as the 103-1000, the 103-1200 and the 301 series. A total of 7 sets, 70 units, have been built by Nippon Sharyo and Kawasaki Heavy Industries. The light and dark blue colored stripes are a good feature of this train. For your information, light blue is "the line color" of the Tozai Line.
The following photo is the EMU 2000 series directly operated from the Toyo Rapid Line. The 2000 series was launched in 2004. A total of 11 sets, 110 units, have been built by Hitachi. This model has been jointly developed with Tokyo Metro. So, the specification of this train is the same as that of 13th batch of the EMU Tokyo Metro 05 series.