JR East, which has yet to identify the cause of the series of vehicle failures on the Yamagata Shinkansen’s new E8 series trains, will continue to reduce the number of Tsubasa trains at least through July 2025.
Failures also discovered in E8 series trains at the depot
Around 11:24 on June 17 (Tue), 2025, a vehicle failure occurred on an E8 series train operating as a deadhead train between Utsunomiya Station and Nasu-Shiobara Station on the Tohoku Shinkansen, rendering it unable to run on the main line for a long period of time. On the same day, two other commercial trains and one deadhead train also experienced vehicle failures, both of which were E8 series trains. The common reason for the inability to run was that the auxiliary power supply unit, which supplies power to each device on the train, broke down, making it impossible to drive the motor.
A detailed investigation by JR East and the manufacturer found damage to the semiconductor elements inside the unit, and an interim report on Wednesday, July 9 stated that the cause of this has not yet been identified. In addition, the company announced that a fault in the auxiliary power supply unit was also found in one E8 series train that was parked at the depot. The company will continue to investigate the cause from a broad perspective, including environmental factors such as temperature, and take necessary measures.
Transfers at Fukushima Station to be partially resolved
Due to the current suspension of all E8 series single-car operation on both the Shinkansen and conventional lines, Yamagata Shinkansen “Tsubasa” trains are suspended on some or all sections, and as a general rule, trains are turning around at Fukushima Station to Yamagata Station and Shinjo Station. As transfers at Fukushima Station have caused congestion on the Tohoku Shinkansen trains, the number of “Yamabiko” trains, which are operated with 17 cars, will be increased from July 19 (Sat), when the summer vacation period begins, and cars 11 to 17 of the additional cars will be reserved seats except for some trains. In preparation for this, the E8 series trains parked on the Yamagata Shinkansen will be gradually transferred to the Tohoku Shinkansen during the night, but the number of trains between Fukushima Station and Yamagata Station will be reduced due to the limited number of rollingstocks available.
Currently, there is only one round trip per day for the “Tsubasa” trains that go directly to Tokyo Station without the need to transfer at Fukushima Station, but this will be expanded to three round trips from July 19 (Sat). The outbound trains are “Tsubasa 127” (departing Tokyo Station at 8:07), “135” (11:00), and “153” (18:00), and the inbound trains are “Tsubasa 128” (departing Yamagata Station at 8:03), “146” (15:03), and “156” (departing Shinjo Station at 17:12). These measures will continue to be implemented throughout July, and a separate announcement will be made regarding the measures for August and beyond.
