Before Shinkansen was constructed, when demands for transportation through railway lines and roads increased corresponding to domestic restoration in the post-war era, both capacities of transporting passengers and of transporting cargo on the Tokaido main line, the most important trunk line in Japan at that time, almost reached their limits.
これに先立ち、戦後の復興と共に鉄道及び道路輸送の需要が増大すると、当時の日本における最重要幹線であった東海道本線の貨客輸送能力は、ほぼ限界に達していた。