East Japan Railway Co. suspended part of train services on the Yamanote and Keihin-Tohoku Lines for about 9½ hours Sunday after four unused cable poles collapsed between Kanda Station and Akihabara Station.
The suspension affected about 410,000 people, JR East said later in the day.
The rail operator said that it discovered that the poles were leaning Friday but decided to fix them Monday after judging that they were unlikely to immediately collapse.
All Yamanote Line services were suspended briefly but services between Ikebukuro Station and Tamachi Station on one of the two loop lines were restored by 10 a.m. Shortly before 4 p.m., all services on Yamanote Line and Keihin-Tohoku Line were resumed.
A Keihin-Tohoku train engineer discovered the collapsed poles around 6:10 a.m.
According to JR East, the two pairs of unused steel poles were found leaning or collapsing on the Yamanote Line’s elevated tracks some 250 meters away from Akihabara Station in the direction of Kanda Station.