The 6-door train cars are disappearing from Tokyo's train lines.
RIP in pepperoni 6-door cars.
They're being removed because of the installation of platform edge doors in the run up to the 2020 Olympics, which requires standardized door positioning (only 2-3 cars per organization were 6 door cars); hence the 6-door cars are being scrapped and replaced by 4-door cars.
205 series trains on the Saikyo Line and Hamasen had 6-door cars but they were scrapped when the new E233s were rolled out. The Yamanote Line already got rid of their 6-door E231-500 series cars. None of these lines' respective vehicles (E233-7000 series, E233-6000 series, E235 series) have 6-door cars. The Chuo-Sobu Line recently scrapped all their 6-door E231-0 series cars.
Meanwhile on Dento, 6-door cars (Tokyu 5000 series) are already being scrapped. The first stations will have retrofitting of platform edge doors completed by the end of this year, and all stations will have them installed by 2018, according to Tokyu's official website:
http://ii.tokyu.co.jp/homedoor/What I liked about 6-door cars is that the seats could be folded up to make them all-standing cars. Really cut down on the manin densha and oshiya.
I wonder if the removal is going to cut down on train capacity by a substantial amount. Perhaps it will be counteracted by the construction of additional subway lines on Tokyo's waterfront, to take some of the load off the Tozai subway line.