About suspension of operation of municipal subway blue line (turn-off operation) (final report)

At 7:15 pm on December 19th, a return operation was carried out by detecting abnormal current between Isezaki-Chojamachi Station and Yoshinocho Station at a substation, but safety confirmation was completed at 11:40 pm As it has been completed, the operation will resume.
We apologize for any inconvenience this may have caused to you.

1 Overview of driving problems
（1） Date and time of occurrence
　　 7:15 pm Tuesday, December 19, 2023

（2） Location of occurrence
　　 Municipal Subway Blue Line between Isezaki-Chojamachi Station and Yoshinocho Station

（3） Progress, etc.
　　 7:15 pm The abnormal current between Isezaki-Chojamachi Station and Yoshinocho Station is detected at substations.
　　 7:16 p.m. All-line operation suspension
　　 8:04 pm Return operation between Kami-Ooka Station and Shonandai Station
　　 8:11 pm Return operation between Azamino Station and Yokohama Station
　　 11:40 pm Safety Confirmation Completed
　　 Operation scheduled to resume at 0:10 am

2 Impact Personnel
　　 Approximately 50,000 people

3 Cause
　　 The curing net installed on the ceiling of the tunnel between Isezaki-Chojamachi Station and Bandobashi Station and the wire that kept it came off and fell.
　 As a result, short circuits between the third rail and the running rail, excessive current flows, resulting in a power outage.

　　 ※Third rail
　　 　Next to the running rail, a rail for power supply called the third rail (the third rail) is installed, and power collection shoes equivalent to a pantograph.
　　 　A method of supplying electricity to a train using a power collection device called (collector Shoo).