Has There Ever Been a Proposal for a Unified Shinkansen Route on the Tohoku and Tokaido Lines?

During the days of the Japan National Railway (JNR), there were proposals to enable the Shinkansen to run through both the Tohoku and Tokaido high-speed railway lines. This discussion delves into the history and challenges behind such proposals and sheds light on the current status of railway infrastructure in Japan.

Platform Configuration and Initial Plans

Throughout the years of JNR, it was envisioned to create a seamless connection between the Tohoku and Tokaido Shinkansen lines. This initiative would require extensive planning and integration of platforms and tracks. The Tohoku Shinkansen lines are identified by the circles 1 and 2, located at the northern part of the railway station. These platforms are equipped for the Tohoku Shinkansen, a network serving the northeast regions of Japan.

Similarly, the platforms designated by circles 4 and 5, positioned at the southern part of the station, are exclusively for the Tokaido Shinkansen. This line primarily catered to the eastern coast, connecting the southern part of Honshu with the western part. Circle 3, which is curved, was initially intended to serve as a transitional platform to facilitate the transfer between different Shinkansen lines. However, technical limitations meant that it was not fully integrated with the Tohoku Shinkansen.

Technical and Operational Challenges

The integration of the Tohoku and Tokaido lines was met with significant operational and technical challenges. While the platforms were designed to be compatible, the train systems themselves needed to be designed to handle both 50/60Hz AC current and different protection systems. This meant that in a merged system, the speed limits and signaling systems would need to be harmonized, a task that proved daunting.

Trains running through the Tohoku Shinkansen would display a 240 km/h speed limit, whereas those on the Tokaido Shinkansen would show a 220 km/h limit or even an error on the display. Ensuring these conditions would allow seamless operation between different railway zones was critical but complex.

Economic Implications and Current Operational Status

The economic implications of running a unified Shinkansen route on the Tohoku and Tokaido lines were also significant. With the Shinkansen connecting different companies (JR East and JR Central) and serving various regions, the revenue distribution was another hurdle. For instance, if a passenger traveled from Ueno to Nagoya, traversing both the Tohoku and Tokaido lines, the revenue split between the two companies was not straightforward.

Due to operational constraints and jurisdiction issues, JR Central ultimately rejected the proposal. The Tohoku Shinkansen trains primarily use tracks that belonged to JR Central before JNR’s bankruptcy, although the facilities were designed for the Tohoku Shinkansen. JR Central reserves the right to run Tohoku Shinkansen trains for free on the tracks owned by JR East, a situation that remains unchanged to this day.

For the current state of affairs, the integration of the Tohoku and Tokaido lines remains a dream left unfulfilled, with the existing facilities serving their respective networks. This divided but interconnected railway system demonstrates the complex nature of railway infrastructure in Japan.