Thousands of commuters, many returning from a fireworks display in Yokohama, were stranded on trains or forced to walk along railway tracks on Tuesday night after broken overhead power lines knocked out services across multiple lines.
East Japan Railway Co., which is investigating the cause of the incident, said Wednesday it believed power supply cables somehow short-circuited, and a spark and extreme heat broke a trolley line at around 7:10 p.m.
The trolley line was found broken in two places between Yokohama and Sakuragicho stations.