On June 17, 2025, JR East released details regarding a mechanical failure involving an E8 series train on the Tohoku Shinkansen between Utsunomiya and Nasushiobara.
🚨 Incident Overview
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Date & Time: Tuesday, June 17, around 11:24 AM
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Train: E8 series out-of-service (non-revenue) test run
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Location: Between Utsunomiya and Nasushiobara
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Issue: The train came to a halt due to a mechanical failure, impacting following scheduled services.
🚄 Impact Summary
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Service Suspension: Operations were suspended system-wide for approximately 6 hours, until around 5:00 PM.
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Affected Lines: Tohoku, Yamagata, and Akita Shinkansen
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Cancellations: A total of 86 trains (both directions) were canceled.
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Passengers Affected: Approximately 54,700 people
⚙️ Cause of Failure (Preliminary)
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The faulty unit was a newly delivered E8 series built by Kawasaki Heavy Industries, completed on June 10, 2025.
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This was the second test run for this train.
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A failure in the auxiliary power supply unit led to no power being delivered to the main converter, which in turn caused the cooling system to stop functioning.
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As a result, circuit protection mechanisms activated, the motors stopped, and the train became unable to move.
🔍 Note: The root cause is still under investigation.
🧩 Related Incidents (Same Day)
JR East is also investigating the possibility of a broader issue, as other E8 series trains also experienced problems on the same day:
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"Tsubasa 136" at Oyama Station
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A non-revenue E8 series at Koriyama Station
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"Tsubasa 139" on the Yamagata Shinkansen
Investigations are underway to determine if there is any common cause among these malfunctions.
