The E4 series shinkansen bullet train is the second series of double-decker Shinkansen trainsets, operating on the Tōhoku, Jōetsu Shinkansen, and occasionally Nagano Shinkansen. The E4 series trains feature double-decker cars to accommodate additional commuter traffic around Tokyo and other urban areas. The E4 series were often coupled to 400 series trains on the Tōhoku Shinkansen between Tokyo and Fukushima before the latter retired in April 2010.
Two eight-car sets can be coupled together for extra capacity, the 16 car trainset can carry a total of 1,634 seated passengers, the highest-capacity high-speed rail trainset in the world. 26 units were built between 1997 and 2003.