Overview

• Investigators traced the June failures to a mismatch between summer-2024 semiconductor parts and specific control boards that caused excessive current and tripped protection devices
• Between June 17 and July 31, JR East canceled over 1,400 Yamagata Shinkansen services, forcing more than 360,000 passengers to transfer to older E3 trains at Fukushima Station
• On August 1, solo E8 operations restored 16 daily round trips between Tokyo and Yamagata/Shinjō, eliminating the need for mandatory transfers at Fukushima
• During the disruption, through-running on the Fukushima–Shinjō section fell to just 1–3 return trips per day under E3-only service
• JR East will maintain heightened operational oversight throughout the Obon travel period to guard against further technical faults