YOKOHAMA -- The operator of the automated train service that ran in the wrong direction here on June 1 and left 14 passengers injured announced on June 6 that there was a break in the circuit detecting the train's direction of travel.
The trains on the line run unstaffed and their movement is controlled by the service's Automatic Train Operation (ATO). The line's operator, Yokohama Seaside Line Co., says the ATO system instructed the train to move correctly, but it was possible that a failure to relay the information due to a break in the wiring lead the train to move in the wrong direction.
On the night of June 1, the Seaside Line service comprising five cars traveling from Shin-Sugita Station for Namiki-Chuo Station ran opposite to its intended direction and hit a buffer stop. According to the operating company, communication between ATO equipment at Shin-Sugita Station and on the train regarding its departure was exchanged correctly, but there was a break in the wiring of the circuit that detects the train's direction of travel in accordance with the information relayed.
The train that had entered Shin-Sugita Station was supposed to change its trajectory and backtrack out to leave the station. But the break in the wiring situated between the front car and the second car meant information to change the direction of travel appears not to have been conveyed. The cables are situated under the train's floor space, with no system in place to detect potential breakages. The company says it inspected equipment in 2017.
Since opening for business in 1989, the Seaside Line has had no major accidents. From June 4 service resumed with staffed trains, but there is currently no indication as to when it will return to automated operations. The government's Japan Transport Safety Board is continuing investigations into a detailed cause of the failure.
(Japanese original by Shotaro Kinoshita, Yokohama Bureau)