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In railways, the process of supplying electricity to trains by methods such as stringing overhead wires (electric wires) above the tracks is called "electrification." Generally, vehicles that run on railway tracks are often called "electric trains," and as the name suggests, electric trains are vehicles that run on electricity. Therefore, electric trains can generally only run on electrified lines. On non-electrified lines, steam locomotives used to run, and as time went on, diesel locomotives and railcars that ran on light oil came into use.
What we will be looking at today is the fact that some sections of the Ou Main Line, which connects the four prefectures of Fukushima, Yamagata, Akita, and Aomori in the Tohoku region, are about to be "de-electrified," meaning that trains will no longer be able to run on the line, which is the opposite of electrification
What is the Ou Main Line?
The Ou Main Line is a 484.5km long JR East line that runs from Fukushima Station in Fukushima Prefecture, through Yamagata Station in Yamagata Prefecture and Akita Station in Akita Prefecture, to Aomori Station in Aomori Prefecture. It was once the fastest route connecting the Tokyo metropolitan area to Akita Station, and trains such as the limited express "Tsubasa" and express "Oga" connecting Ueno Station in Tokyo and Akita Station, as well as the sleeper limited express "Akebono" and express "Tsugaru" connecting Ueno Station and Aomori Station via the Ou Main Line, operated on this line.
The Ou Main Line, a vital trunk line running through four prefectures in the Tohoku region, began to be electrified shortly after the war, enabling electric trains and locomotives to operate on it. First, in 1949, the section between Fukushima Station and Yonezawa Station, which includes the notoriously difficult Itaya Pass, was electrified.
From 1960 onward, electrification progressed in other sections as well, and in 1975, electrification of the entire Ou Main Line with AC 50Hz, 20,000V was completed. The significance of electrifying the entire line was great, and the 485 series electric train, which can be said to be representative of the limited express trains of the JNR era, was introduced to the "Tsubasa" limited express train connecting Ueno Station and Akita Station.
Limited express "Tsubasa" operated by 485 series electric trains (photo taken after the launch of JR)
A major turning point for the Ou Main Line was the opening of the Yamagata Shinkansen in 1992. To accommodate Shinkansen trains, the track gauge (the distance between the two rails) between Fukushima Station and Yamagata Station on the Ou Main Line was widened from the conventional narrow gauge of 1,067 mm to the standard gauge of 1,435 mm, which is suitable for Shinkansen trains. Naturally, conventional narrow-gauge trains cannot run on the tracks that have been converted to standard gauge. While the effect of direct Shinkansen service from the Tokyo metropolitan area to Yamagata is significant, the Ou Main Line's role in providing direct train service between the Tokyo metropolitan area/Fukushima and Akita/Aomori was lost from this point onward.
The Yamagata Shinkansen was extended from Yamagata Station to Shinjo Station in 1999. Therefore, the track gauge in this section is now standard gauge. between Yamagata Station and Shinjo/Akita StationKomakusa, but it was discontinued as a limited express train with the extension of the Yamagata Shinkansen to Shinjo, and became a rapid train operating only north of Shinjo Station. The rapid "Komakusa" was also discontinued in 2002.
Additionally, Akita Shinkansen trains currently run on the Ou Main Line between Omagari Station and Akita Station in Akita Prefecture. However, this section is a double track with two tracks, one being narrow gauge and the other standard gauge, so it remains possible for narrow gauge trains to operate on this line.
Damage to the Ou Main Line between Shinjo Station and Innai Station and the "de-electrification"
The heavy rains that began on July 25, 2024, caused widespread damage in the Tohoku region, and several railway lines were affected. On the Ou Main Line, a 45.8km section from Shinjo Station in Shinjo City, Yamagata Prefecture, to Innai Station, the southernmost station in Yuzawa City, Akita Prefecture, remains suspended as of January 2025. Currently, it has been announced that service will resume before Golden Week in 2025.
Furthermore, the damaged section will not be restored to its original state; it has been explicitly stated that power equipment such as overhead lines will be removed. This is the opposite of electrification; the line will be de-electrified, so perhaps it should be called de-electrification. The state in which the entire Ou Main Line has been electrified for 50 years since 1975 will be dissolved.
JR East states that the reason for de-electrifying the section between Shinjo Station and Innai Station is that it is "sustainable and will allow for faster recovery in the event of a disaster." This announcement itself can be considered reasonable. If the power equipment is removed, there will be no need to restore it in the event of the next disaster, so the time required for recovery will be shorter and the costs required for recovery will be lower. In addition, since the maintenance of the power equipment will not be necessary, the manpower and costs associated with that will also be eliminated.
The obvious disadvantages of de-electrifying the line include the inability to run electric trains and the elimination of through services from other sections. However, as mentioned earlier, the Ou Main Line's role in providing through services over a wide area has already been lost. South of Shinjo Station, the track has been converted to standard gauge for the Yamagata Shinkansen, so there are no trains that run across Shinjo Station in the first place.
In addition, the section between Shinjo Station and Innai Station, in particular, which was hit by the disaster, runs along the border between Yamagata and Akita prefectures, and there is little demand for travel in this area. More precisely, the number of passengers per kilometer per day in this section, or more precisely, between Shinjo Station and Yuzawa Station, was announced to be 291 in fiscal year 2023. With such a small number of users, it is reasonable to assume that there is also little demand for direct travel between the affected section and the section north of Innai Station (although there is room for debate as to whether the demand for travel has decreased as a result of the Ou Main Line being effectively divided by the Yamagata Shinkansen). The decision to remove the power facilities, even if it makes direct train service impossible, is understandable.
In the timetable from March 2024, prior to the disaster, there were hardly any trains that operated solely within the section between Shinjo Station and Innai Station. The vast majority of trains passing through this section ran directly between Shinjo Station and Akita Station. Naturally, most trains were electric trains, with only one round trip per day operated by diesel railcars.
Operation as of March 2024
However, trains that run across Innai Station will naturally no longer be able to operate as electric trains if the section between Shinjo Station and Innai Station becomes non-electrified. While there is a small possibility that trains from Shinjo Station to Akita Station may be operated by diesel railcars, it would be inefficient to use diesel railcars on the section between Innai Station and Akita Station since electric trains can be used there. Therefore, it is unlikely that at least the pre-disaster number of trains (7 round trips per day) will be able to run to Akita Station. The operation of trains passing through the disaster-stricken section is expected to change significantly from before the disaster.
Predicted operation format after resumption of service in 2025
When service resumes, the diesel railcars will most likely operate mainly on sections that can only be run by diesel railcars, namely the unelectrified section between Shinjo Station and Innai Station. However, if all diesel railcar trains turn back at Innai Station towards Shinjo Station, it will be inconvenient for those traveling from Shinjo to Yuzawa Station, which is in the center of Yuzawa City, as they will have to transfer. If there are complaints from users and local municipalities along the line about the inconvenience, the diesel railcar service may be extended to Yuzawa Station. from Innai Station to Yuzawa Station is 16.0 km. Personally, I think it would be worthwhile to extend the service that far. Also, even if not all the way to Akita Station, I personally think there should at least be direct trains to Yokote Station, where it connects with the Kitakami Line.
We won't know what the actual timetable will be until it is announced, but we can only hope that the reduction (or complete elimination) of direct trains that cross Innai Station will not make the Ou Main Line more inconvenient and further reduce the number of passengers
JR East had originally announced its policy to remove power facilities on local lines in 2021. If the Ou Main Line case proves successful, I think there is a possibility that power facilities will be removed on other lines in the future (the narrow-gauge section between Innai Station and Omagari Station on the Ou Main Line, and the section between Omagari Station and Akita Station are likely candidates). From a hobbyist's perspective, it is a little sad to see lines that were once traversed by long-distance express trains become non-electrified, but I sincerely hope that this will have a positive impact on the maintenance of local lines in the future.
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