A JR freight train and a Hokkaido Shinkansen bullet train pass each other in a shared section of the Seikan Tunnel on March 6. (Wataru Sekita)

Hokkaido Railway Co. (JR Hokkaido) has spent a whopping 30 billion yen ($286 million) since fiscal 1999 to plug water leaks, replace rusted pipes and repair other deteriorations in the undersea Seikan Tunnel.

However, the railway company is not content with just fixing the tunnel, which marked its 30th anniversary of operations on March 13. Plans are in the works to raise the speed limit for bullet trains in the 53.85-kilometer tunnel that connects Hokkaido and the main Japanese island of Honshu.

JR Hokkaido also wants to rectify the 25-minute “dead zone” for mobile phone connections that Shinkansen passengers in the tunnel have complained about.

The Seikan Tunnel’s history is filled with ups and downs. It is currently taking measures to ensure passenger numbers in the aging tunnel remain on track.


In 1954, the Toya Maru passenger ferry and four other vessels, including cargo ships, sank in a typhoon that struck the Tsugaru Strait, killing 1,430 people.

The disaster fueled momentum to construct the undersea tunnel. After the passenger ferry service was abolished, trains using the Seikan Tunnel become the main means of crossing the Tsugaru Strait.

In 1988, when the tunnel opened for operations, more than 3 million passengers used it to travel between Honshu and Hokkaido. The annual number later plunged to less than 2 million.

But in fiscal 2016, the number rebounded to the 2-million level for the first time in 21 years. That’s because on March 26, 2016, the Hokkaido Shinkansen Line started services on the section linking Shin-Aomori Station in Aomori Prefecture and Shin-Hakodate-Hokuto Station in Hokuto, Hokkaido.

The economic ripple effects were huge.

In 2017, the number of foreign lodgers in Aomori Prefecture hit a record high of about 239,000, up about 67 percent from the previous year. It was the sharpest growth among all prefectures in Japan.

“With the opening of the Hokkaido Shinkansen Line, (Aomori) has become a destination for foreign tourists combined with the popular destination of Hokkaido,” said an official of the Aomori prefectural government.

Nevertheless, the number of tourists who visited Hakodate in fiscal 2017 is expected to drop year on year after a record high in fiscal 2016.

A JR Hokkaido official also said the company will likely fall short of expectations for a large increase in the number of tunnel users by fiscal 2030, when the Hokkaido Shinkansen Line is expected to be extended to Sapporo.


To regain momentum, the financially struggling railway company needs to first deal with problems caused by the aging of the tunnel and its facilities.

In 2014, JR Hokkaido confirmed for the first time that a roadbed had elevated in part of an advancing drift tunnel used for ventilation and drainage, and the width of the tunnel had shrunk. JR Hokkaido has taken measures to fix the problems.

An official in charge of civil engineering works at the company said deterioration is inevitable in a tunnel that is 30 years old.

“It’s difficult to deal with the deterioration because unprecedented incidents could occur,” the official said. “But we will strive to attentively implement measures and maintenance to quickly detect abnormalities.”

The government’s draft budget for next fiscal year also includes support measures for JR Hokkaido to fix the mobile phone connection problem.


JR Hokkaido on March 6 showed the inside of the tunnel to reporters.

At the deepest level of the Seikan Tunnel, 283 meters below the surface, a breeze of 3.6 kph blew through an advancing drift.

Water had constantly gushed into the tunnel from the solid bedrock. Several drainage pumps located in both Hokkaido and Aomori Prefecture had removed about 20 tons of water per minute from the tunnel.

About 1,100 meters of piping that had been sending cooling water to these pumps were rusted.

The replacement of all the corroded pipes was included in the 30 billion yen of repairs and upgrades.

JR Hokkaido also installed disaster prevention equipment in the tunnel for emergencies such as accidents and fires.

The Shinkansen operation control center in Sapporo manages conditions in the tunnel, according to Atsushi Fujita, 58, head of JR Hokkaido’s Hakodate Shinkansen construction department.

Fujita said the control center has developed a number of ways to detect malfunctions.

An aid station and portable toilets were set up in a shelter inside the tunnel that can accommodate 1,000 people. Drinking water, emergency provisions, cold weather protection sheets and other supplies are stored at the station.


To increase passenger numbers, JR Hokkaido wants to raise the speed limit for Shinkansen trains inside the tunnel.

Bullet trains must not exceed 140 kph in the tunnel to prevent the generated wind pressure from knocking off loads on freight trains when they pass by.

That speed limit matches the top speed of conventional limited express trains.

Currently, the fastest Shinkansen trains can connect Tokyo and Shin-Hakodate Hokuto stations in four hours and two minutes.

Starting in spring, the Ministry of Land, Infrastructure, Transport and Tourism and JR Hokkaido will run tests on increasing the maximum speed of bullet trains in the tunnel to 160 kph. The eventual goal is 200 kph so that the service can cover the Tokyo-Hakodate route in less than four hours and compete better against airlines.


On March 6, a freight train departed from Hakodate bound for Aomori.

After traveling for about an hour from Goryokaku Station in Hakodate, the 18-car freight train, towed by an electric locomotive, reached a section of the route shared with Shinkansen.

The shared section features a dual-gauge track using three rails: a Shinkansen rail, a rail for freight trains; and a shared rail for Shinkansen trains and freight trains.

As soon as the freight train left the sub-zero weather and entered the tunnel, where the temperature tops 20 degrees and the humidity level is kept at 80 percent or more, the locomotive became shrouded in mist.

A small white light appeared in the distance. It was a Hayabusa (Peregrine falcon) No. 19 bullet train that had departed from Tokyo Station and was heading for Shin-Hakodate-Hokuto Station.

The sleek Hayabusa is among the fastest of all Shinkansen trains. If it had gone through the tunnel at its top speed, the strong air pressure created would likely have dislodged the onions, potatoes and auto parts from the fully loaded freight train.

Instead, driving within the 140 kph speed limit, the bullet train, with the distinctive long green nose of the lead car, and the freight train passed each other without incident.

After the freight train traveled for 37 minutes through the Seikan Tunnel, snow falling on the Tsugaru Strait came into view on the left.

“This is the only section that Shinkansen and freight trains share in Japan,” said Daisuke Takahashi, the 43-year-old driver of the freight train who has 23 years of experience on the job. “Driving a train on this section is my secret pride.”

(This article was compiled from reports by Hiroaki Abe, Son Yummin and Hitoshi Kujiraoka)