Japan’s Shinkansen: Its Wonders and Woes ⑤ – The Impact of the Switch

In previous articles, we discussed the weaknesses of the Shinkansen from the perspective of its “maximum service speed” and “tracks.” Next, we will talk about the limitations posed by the Shinkansen’s “switches (points).”

Major starting stations like Tokyo Station or Shin-Osaka Station have multiple platforms where many trains arrive, stop, and then depart “slowly.” Even at large intermediate stations, trains tend to accelerate “gently.” In a typical station structure, there are straight tracks in the center for through trains, and on the platform side, there are tracks that serve both as passing loops (siding) and platforms for passengers to board and alight. When looking at this basic station structure, have you ever noticed something? Yes, whether a train is arriving or departing, it never accelerates rapidly; it always moves “slowly.” The reason is simple: there are switches installed immediately before and after the station. Furthermore, these switches impose a surprisingly low “speed limit of 70 km/h,” which seems unnatural for a high-speed Shinkansen. If you recall the sight of long Shinkansen trains weaving in and out of stations, it must have looked like that. That scene is impossible for any railway claiming to be ‘high-speed.’ Japan’s Shinkansen is perhaps unmatched globally in this regard.
The fundamental principle of a high-speed railway is eliminating speed restrictions that interfere with high-speed operation. Therefore, the 70 km/h limit on a Shinkansen that wants to race along at full throttle of 320 km/h is quite disappointing. The French TGV uses something called a “65th switch,” and it can maintain up to “220 km/h” even when diverging from the main line—that’s remarkable! In fact, while Japan’s Shinkansen cannot match the TGV’s 220 km/h, there are switches that impose a “speed limit of 160 km.” These are called the “38th switch” and were installed around Takasaki Station in Gunma Prefecture when the Nagano Shinkansen opened for the Olympics. They are located at the current junction points between the Hokuriku Shinkansen and the Joetsu Shinkansen. Since then, they have been introduced across many other lines… yet even today, many Shinkansen stations still retain the 70 km/h speed limit. The movable section of that switch is an impressive 1,400 meters long, making it impractical to install in locations like Tokyo or Shin-Osaka. This serves as a major obstacle to acceleration, but changing existing railway infrastructure once it has been built seems incredibly difficult.

There are several obstacles hindering high-speed operation, such as the smaller cross-sectional area compared to foreign tunnels or the close passing distance between trains. We plan to discuss these next time.

See you again!

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