Trains on East Japan Railway’s Yamanote and Keihin-Tohoku lines were halted in all directions with no timetable for resumption, the railway said.

A fire was reported on the tracks near Tamachi Station, where both lines stop, shortly before 8am (2300 GMT on Thursday), public broadcaster NHK said. Flames were coming from a transformer in the track area, and the fire was nearly extinguished about 30 minutes later, NHK said.

Passengers were seen disembarking from a Keihin-Tohoku train stranded between stations and walking along the tracks to evacuate, assisted by firefighters and railway staff, in footage broadcast by the NTV network.

The Yamanote Line passes through stations including Shinjuku, which handles about 3.5 million passengers daily. The Keihin-Tohoku Line serves major hubs such as Tokyo and Yokohama.