On September 26, JR East announced the results of its investigation into the incident where the Tohoku Shinkansen Hayabusa and Komachi No. 6 bound for Tokyo made an emergency stop after the train became uncoupled while traveling between Furukawa and Sendai in Miyagi Prefecture on September 19. According to the report, a metal fragment was found near the switch that controls the train's coupling mechanism, which is believed to have caused the malfunction. The metal fragment is suspected to have been left over from the manufacturing process of the vehicle.
