OSAKA -- Miscommunication between maintenance staff and train controllers let potentially disastrous damage to one of Japan's shinkansen bullet trains go unaddressed for about three hours, despite an inspection being suggested.
A train experiencing unusual noise, odors and vibrations was allowed to run from Hakata Station, in the southwestern city of Fukuoka, all the way to Nagoya before being taken out of service when a roughly 14cm crack was discovered in the undercarriage of one of the cars. Had the crack widened just 3cm more, the frame could have split, potentially derailing the train.
The Japan Transport Safety Board is looking into the matter as a serious incident -- the first ever involving the country's celebrated high-speed-train network.
President Tatsuo Kijima of railway operator JR West laid out a timeline for reporters Wednesday, highlighting failures of communication between operators and controllers. "Problems with the entire shinkansen operating system" played into the events, Kijima said.
The missed call
A conductor aboard the train heard a high-pitched noise soon after departing Hakata on the afternoon of Dec. 11. Later, multiple crew members noted unusual sounds, as well as a burnt smell, strange vibrations and a haze inside the train, according to JR West's version of events.
Maintenance staff boarded in Okayama, and a worker telephoned the nationwide shinkansen control center in Tokyo. The worker initially reported that the problem did not seem serious enough to affect the train's operation, suggesting that a safety check be performed in Osaka, where the train would be stopping shortly. But right when this proposal was made, the controller was talking to a superior nearby and "didn't hear" the suggestion, according to the report.
The maintenance crew assumed that controllers had arranged for a safety check somewhere down the line. The control center, meanwhile, assumed that any serious problems would have been clearly reported and so neglected to make the arrangements.
When the train reached Osaka, JR West saw no reason that it could not continue its run and handed over control to JR Tokai, which operates bullet trains between Osaka and Tokyo. It was not until the train reached Nagoya around three hours after it departed Hakata that it was inspected, revealing the crack, according to the report.
In light of the incident, JR West has updated guidelines for judging when to take trains out of service. Unusual odors and vibrations, in addition to strange noises, now factor into such decisions. The opinions of crew members on the scene, such as conductors and maintenance workers, are to carry the most weight when making these judgments.
"There was overconfidence in the high level of safety of shinkansen trains, and it dulled our sense that accidents can occur," said Norihiko Yoshie, head of railway operations, at the news conference.
Satoru Sone, a professor of railway engineering at Tokyo's Kogakuin University, said action should have been taken sooner.
"There were a number a signals," Sone said. "An inspection should have been performed to determine the problem no later than Shin-Osaka Station."
JR East is also updating its operating procedures to require an inspection when a burnt smell is detected. JR Tokai already requires conductors and controllers to tell others when smoke or a strange smell is noticed.