History of the Usui Main Line

The Usui Line ran between Yokokawa (Gunma Prefecture) and Karuizawa (Nagano Prefecture) for 11.2 kilometers. It began service in 1893, only a year and a half after construction began.

Trains began running between Takasaki and Yokokawa in 1885, and between Naoetsu (Niigata Prefecture) and Karuizawa in 1888. These lines directly connected Tokyo, Gunma, Nagano, and Niigata. The opening of the Usui Line allowed Japan to begin the mass exportation of raw silk from Nagano and Gunma to Tokyo / Yokohama, and from there to Europe and other countries.

Brick Bridges and Tunnels Through Precipitous Terrain


There are only 11.2 kilometers between Yokokawa and Karuizawa, but the difference in elevation is 552.5 meters, and the slope is as steep as 66.7 per mille (67.7 vertical meters per 1,000 meters traveled). Because of this, the Abt system used by the German company Harz Narrow Gauge Railways was adopted for the Usui Line. The Abt system uses a special toothed rail in the center of the tracks called a rack rail. The train cars are fitted with cog wheels, or pinions, which catch on the rack rail to help overcome steep gradients. With 26 tunnels and 18 bridges along the Usui Line route, you can imagine just how steep the incline can be.

Approximately 18,010,000 bricks were used to construct the collective tunnels and bridges of the Usui Line. The third bridge along the line from Yokokawa is called Megane Bridge. 91 meters long, 31 meters high, and consisting of approximately 2,030,000 bricks, it is the largest arched brick bridge in Japan.

The EF63 Electric Train: the birth of Japan’s first Abt System Electric Train, an Important Innovation of its Time



The 26 tunnels along the Usui Line made it impossible to use traditional steam locomotives. If such a train passed through these tunnels, the smoke would have nowhere to go and might suffocate the conductor and passengers. This is why Japan’s first electric train using the Abt system was developed and began service in 1912. To supply electricity along this route, a thermal power station was built near Yokokawa Station, as well as several other electrical substations in the area.

With time, the relatively slow Abt system was unable to meet the increased demand for freight and passenger transportation. Therefore, the Usui New Line (Usui Shinsen) was established in 1963 along with the EF63 which maximized weight capacity. With this new train model, more freight could be carried along the Usui Line than ever before.

The End of Usui Line’s 104-year History


In 1993, the Usui Line’s contribution to the industrialization of Japan was acknowledged when Usui Pass Railways was designated it as an Important Cultural Property of Japan. It was the first “modern heritage” to ever be designated.

Despite this, however, the Usui Line’s 104-year history came to an end when the line closed its service in September of 1997, the same month the Nagano (Hokuriku) Shinkansen Line began service.

The “Abt Road” was established in 2001 as a pedestrian path along the abandoned Usui Line tracks between Yokokawa and Megane Bridge. In 2012, it was extended as far as Kumanodaira Station.