E4 Double decker shinkansen. The E4 series of Shinkansen trains — known for their Max Toki and Max Tanigawa services on the Joetsu Shinkansen line — will retire after their final run on Oct. 1. The E4 are the only double-decker Shinkansen trains in Japan. Social media accounts operated by East Japan Railway Co. have been flooded with messages from passengers and fans, describing their memories of trips and expressing their appreciation.