East Japan Railway Co. said Monday it found that a 15-meter stretch of track on Tokyo's Yamanote Line had subsided by up to 2 cm.
At around 7 a.m., a JR East driver reported that his train shook abnormally when traveling between Shinbashi and Hamamatsucho stations. Other drivers later reported the same problem.
JR East said there is a high possibility the problem may be related to street construction being carried out near the section. The carrier halted operations for three hours on one set of the loop line's tracks to carry out checks.
Some 112,000 morning rush-hour passengers were affected before operations resumed at around 10:45 a.m.
"We were stuck on the train for a long time after it left a station," a 57-year-old woman caught in the delay said.
