Tohoku and Joetsu Shinkansen opened in 1982. While Tokaido and Sanyo Shinkansen lines are integrally operated, these two lines are specifically searated. Since they run northern area in Tokyo, stocks and tracks are designed to be ready for coldness and snow. As Yamagata and Akita shinkansen were rebuilt from normal narrow-gauge lines, stockss in these lines are smaller than normal Shinkansen stocks.