All shinkansen services in eastern Japan ground to a halt for 75 minutes Monday morning during a control system failure.
Fifteen runs were canceled and 124 others delayed by up to 2 hours and 13 minutes, affecting at least 81,200 people scheduled to ride the Tohoku, Joetsu, Nagano, Yamagata and Akita shinkansen lines, which were closed from 8:23 to 9:38 a.m., according to East Japan Railway Co.
Normal operations had resumed by the afternoon, JR East said.
JR East said the disruptions were caused by a failure in COSMOS, the main system responsible for controlling its bullet train operations. When the system failed, the computer screens froze and ceased to function, the railway said.
The malfunctions are believed to have taken place in parts of the COSMOS network that control train schedules, track signals and other equipment, the carrier said.
The system failure hit two days after services were suspended on the Tohoku, Yamagata and Akita lines due to electrical system and signal failures Saturday at a station on the Tohoku Line.
The Tokaido Shinkansen Line, meanwhile, operated behind schedule Monday as well due to snow-related problems that started the previous day.
JR East experienced a similar system failure on Dec. 29, 2008, that stopped more than 100 bullet trains.