The Nippori-Sajin Liner that runs in Arakawa Ward and Adachi Ward in Tokyo has been suspended for 4 days in a row. The power outage in the early morning of the 4th and 10th of this month was caused by a damaged or defective pantograph.
The Tokyo Metropolitan Transportation Bureau said, "We sincerely apologize for any inconvenience and concern caused to our customers, and we will take all possible measures to investigate the cause and prevent recurrence" The cause of the bolt coming off is under investigation.