Yamagata Shinkansen has been operating with significantly reduced services for nearly a month due to train faults. The line has been severely disrupted in summer, and it may have a huge negative impact on local economy.
On 17th June, Tohoku Shinkansen was closed for 5.5 hours due to broken down trains. Initially, it was reported that the newest unit of E8 series came to a halt because of fatal technical failure whilst testing, but according to Nikkei, three more units suffered from similar failure on the same day. According to JR East, a power system on each units that converts power for other devices broke down so that a cooling system stopped, and thus the trains could not reactivate. It was later found that the power system was severely damaged or even partly melted. The cause of the troubles remains unknown.
The E8 series entered into service in March 2024, and eleven seven-carriage units have been introduced as of today. Five of them have been taken out of service and are under investigation. JR East timidly reinstated other units to passenger services, but the company has decided to use the units always with 10-car E5 series trains. They are used only for a handful Yamabiko services between Tokyo and Sendai. In other words, the company has not used the E8 series units independently since then.
As a result, there has been a severe shortage of trains. JR East has been using E3 series trains alongside the E8 series, but the E8 series trains have been unable to engage in passenger services between Fukushima and Shinjo, so all Yamagata Shinkansen services are provided by old E3 series trains. However, the number of the E3 series is not sufficient, as the old trains have been gradually replaced with the E8 series. Hence, Nikkei estimated that the daily capacity would decrease by up to 40%.
JR East had no choice but to cancel almost of all direct services between Tokyo and Yamagata or Shinjo. According to the temporary timetables, E3 series trains run between Fukushima and Shinjo, and all passengers to and from Tokyo or Omiya are required to change trains at Fukushima station. As trains have to wait for the transfer, there have been minor delays on some services.
JR East and manufacturers are struggling to figure out the cause. Hence, JR East announced on Wednesday that the service reduction will continue until at least the end of July. Amidst concerns over local economy, Asahi Shimbun reported that the Governor of Yamagata Prefecture urged JR East to carry out all the necessary investigations and resume the services as soon as possible. In response to her request, JR East decided to provide three direct trains to and from Tokyo from Saturday 19th July using the E3 series, but there will be even fewer services between Fukushima and Shinjo due to lack of available trains. At present, it is highly uncertain if all E8 series will be reinstated before Obon holidays in mid-August, one of the busiest seasons in Japan.