JR firms hone earthquake-response systems for shinkansen lines

Kyodo

On Oct. 23, 2004, at 5:56 p.m., the first shinkansen derailment in history occurred when a bullet train en route from Tokyo to Niigata went off the tracks following a powerful earthquake in the Chuetsu region in Niigata Prefecture.

Toki No. 325 was cruising at 204 kph on the Joetsu Shinkansen Line between Urasa and Nagaoka stations when the temblor hit.

But a major catastrophe was avoided when the train straddled a trackside rail, causing it to grind to a halt with carriages only tilted to the side, rather than flipped.

“The bag on the rack grazed my head when it came flying by. It was amazing no one was killed,” said Tsugio Saito, an 84-year-old film producer from Yokohama who was a passenger on that day.

Eight of the train’s 10 cars derailed, with the four rear cars derailing completely. But none of the 155 passengers or crew was seriously injured.

A potential second accident was avoided when car No. 1 swung around nearly 30 degrees and was almost lying across the parallel track, leaving it vulnerable to a collision with a train coming from the opposite direction. But fate intervened.

Still, it was the first bullet train to derail since Japan started high-speed railway services in 1964.

Confronted with major disasters such as the Great Hanshin Earthquake in 1995 and the 2011 Great East Japan Earthquake, Japan Railway companies have been devising ways to better prepare for a repeat event.

Following the derailment on the Joetsu Shinkansen Line, East Japan Railway Co. developed a metal fitting called an L-shaped guide, which is attached to the outside of the wheel, and according to the company “prevents deviation from rails by controlling the (large) lateral displacement of cars.”

After its safety function was proved, the device was subsequently installed on all JR East shinkansen trains in service, the company said.

Similar devices have been introduced by other JR companies. Following the Kumamoto earthquake that derailed an out-of-service bullet train last April, JR Kyushu has been working to install “derailment-prevention guards,” which are designed to stop train wheels from veering off the tracks by sandwiching them with the rail.

Nevertheless, when protecting bullet trains from earthquakes, detection is paramount in situations in which seconds are a matter of life and death. For this, improvements in early warning systems that detect preliminary tremors are essential.

Shinji Sato works for the Railway Technical Research Institute, where he is involved in developing early warning systems that detect P-waves — the first detectable evidence from an earthquake that arrives in a seismograph.

According to Sato, research began in the 1970s and full-scale operation of early warning systems began in 1992.

A major accident was avoided during the 2011 Great East Japan Earthquake because of the emergency stop system, although a Tohoku Shinkansen train making a test run did derail with minimal damage.

JR East’s Urgent Earthquake Detection and Alarm System is made up of seismometers installed at over 100 locations. When they detect earthquake-induced tremors, they determine the expected effect and send out warning signals to cut the power supply to trains.

“Even more effort is necessary to accurately detect (earthquakes) even faster,” Sato said.

Even if bullet trains can be safely stopped during disasters, stations, elevated bridges and other structures are still at risk of serious damage. This was a lesson learned during the Great Hanshin Earthquake.

“We learned for the first time that there are massive earthquakes that we could never have imagined,” said Tadayoshi Ishibashi, 69, a JR East adviser.

The most vulnerable infrastructure has been looked at to lessen the chances of major damage. Concrete bridge supports, which do not contain reinforcement steel, or embankments whose earthquake-resistant properties are a cause for concern, have been reinforced.

This was why, experts say, severe damage across the railway system was avoided during the Tohoku earthquake and tsunami.

Ishibashi, however, said there was no substitute for experience when it came to earthquakes.

“Without experience, technology will wane. Unless we enhance training, swift recovery becomes difficult,” Ishibashi said.