JR East Shinkansen Train Services were Disrupted Possibly by Loosened Overhead Cables Caused by Damage to Cable Weight (UPDATE 1)

The Yomiuri Shimbun
Shinkansen train halted on the tracks in Saitama on Tuesday morning.

East Japan Railway Co. (JR East) announced Wednesday that a part of a steel weight used to pull an overhead cable had been found broken regarding the power outage that disrupted Shinkansen bullet train services. The power outage was likely due to the Shinkansen train system shutting down its electric supply when it detected its contact with a dangling cable as an anomaly. It plans to conduct emergency inspections on the rest of the weights used in all JR East Shinkansen lines.

The Tohoku, Joetsu and Hokuriku Shinkansen bullet train services were suspended Tuesday due to the outage.

The Yomiuri Shimbun

According to the company, steel weights, each about 1.3 tons, are installed on utility poles with wires along the tracks to fasten the overhead power lines. At a site in Chuo Ward, Saitama City, where workers found an overhead cable dangling after the power outage was detected, a part connecting the weight to the wire was found broken, causing it to fall.

It is suspected the Hokuriku line Kagayaki bullet train touched this cable as a result when it passed the site.

The type of steel weight that broke is supposed to be replaced about every 30 years, but the weight in question was installed in 1985 and had been used for 38 years, the firm said. In principle, replacement time is judged based on the condition and environment it is in.

Emergency inspections are planned at about 500 locations this month. The company also plans checkups for all non-bullet train lines by the beginning of the Golden Week holidays.

JR East said there were no abnormalities found when the same location was inspected in June and October last year. It plans to ask an expert for an analysis to investigate the cause of the breakage.

The Land, Infrastructure, Transport and Tourism Ministry requested the firm in writing to investigate the cause of the incident and take measures to prevent recurrence.