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In the railway industry, "electrification" refers to the ability to supply electricity to vehicles by means of methods such as stringing overhead wires (electrical cables) above the tracks. Generally, vehicles that run on rails are called "trains," but as the name suggests, trains are vehicles that run on electricity. Therefore, trains can generally only run on electrified lines. In the past, steam locomotives ran on non-electrified lines, but as time went on, diesel locomotives and diesel railcars that run on diesel fuel came to be used.
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 JR East line that runs from Fukushima Station in Fukushima Prefecture to Aomori Station in Aomori Prefecture, passing through Yamagata Station in Yamagata Prefecture and Akita Station in Akita Prefecture. This line used to be the fastest route connecting the Tokyo metropolitan area to Akita Station, and featured express and rapid trains such as the Tsubasa Limited Express and Oga Express, which connect Ueno Station in Tokyo with Akita Station, as well as the Akebono Sleeper Express and Tsugaru Express, which connect Ueno Station and Aomori Station via the Ou Main Line.
The Ou Main Line, an important trunk line that runs through four prefectures in the Tohoku region, was electrified shortly after the war to allow trains and electric locomotives to run on it. The first section to be electrified was the section between Fukushima Station and Yonezawa Station, which included the Itaya Pass, a notoriously difficult section of the line, in 1949.
After 1960, electrification progressed to other sections as well, and in 1975, electrification of the entire Ou Main Line with 50Hz, 20,000V AC was completed. The significance of electrifying the entire line was great, and the 485 series electric train, which could be said to be representative of express trains from the JNR era, was introduced on the Tsubasa limited express train that runs between 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. In order to accommodate Shinkansen trains, the track gauge (the distance between two rails) of the Ou Main Line between Fukushima Station and Yamagata Station was widened from the narrow 1,067mm gauge commonly used on conventional lines to the standard 1,435mm gauge, which is suitable for Shinkansen rolling stock. Naturally, the standard gauge tracks meant that the previous narrow gauge rolling stock could not run on them. While the impact of the Shinkansen now running directly from the Tokyo metropolitan area to Yamagata was great, the Ou Main Line's role as a direct train service between the Tokyo metropolitan area and Fukushima and Akita and Aomori was lost from this time on.
The Yamagata Shinkansen was extended from Yamagata Station to Shinjo Station in 1999. Therefore, the track gauge for this section is now standard gauge. Komakusa between Yamagata Station and Shinjo Station/Akita Station , but when the Yamagata Shinkansen was extended to Shinjo, it was discontinued as a limited express and became a rapid train that only ran north of Shinjo Station. The rapid "Komakusa" was also discontinued in 2002.
Additionally, the Akita Shinkansen currently runs between Omagari Station and Akita Station on the Ou Main Line in Akita Prefecture. However, this section is double-track, with one track being narrow gauge and the other being standard gauge, so narrow gauge vehicles can still 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 across the Tohoku region, with several railway lines also affected. As of January 2025, the 45.8 km section of the Ou Main Line between Shinjo Station in Shinjo City, Yamagata Prefecture, and Innai Station, the southernmost station in Yuzawa City, Akita Prefecture, remains suspended. At present, it has been announced that service will resume before Golden Week in 2025.
Furthermore, it has been made clear that the affected sections will not be restored to their original state, but rather that overhead lines and other power facilities will be removed. This is the opposite of electrification, as the line will be de-electrified, so perhaps we should call it de-electrification. The entire Ou Main Line, which has been electrified for 50 years since 1975, will no longer be electrified.
JR East stated that the reason for restoring service by de-electrifying the section between Shinjo Station and Innai Station is that it is "sustainable and will enable faster recovery in the event of a disaster." This announcement itself is reasonable. If the power equipment is removed, there will be no need to restore the power equipment the next time a disaster occurs, which will shorten the time it takes to restore the equipment and reduce the costs required for restoration. In addition, there will be no need to maintain the power equipment, so the manpower and costs involved will also be unnecessary.
The disadvantages of de-electrifying the line are, of course, that trains will no longer be able to run on it, and that trains will no longer be able to run directly from other sections. However, as mentioned above, the Ou Main Line's role of providing direct train service over a wide area has already been lost. The section south of Shinjo Station 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, which is particularly affected by the disaster, crosses the border between Yamagata and Akita prefectures, and travel demand is low; the number of passengers per kilometer per day on this section, or more precisely, between Shinjo Station and Yuzawa Station, is announced to be 291 in fiscal year 2023. With such low ridership, it is likely that there will also not be much demand for direct service between the affected section and the section north of Innai Station (although it is debatable whether the demand for travel has declined as a result of the Yamagata Shinkansen effectively cutting off the Ou Main Line). The decision to remove the power equipment even if it means that direct train service is no longer possible is understandable.
In the timetable for March 2024, before the disaster, there were almost no trains that ran only within the section between Shinjo Station and Innai Station, and most trains that ran through this section operated as direct trains between Shinjo Station and Akita Station. Naturally, most trains were electric, with only one round trip per day by diesel railcar.
Operation as of March 2024
However, if the section between Shinjo Station and Innai Station is de-electrified, trains that run across Innai Station will naturally no longer be able to run as electric trains. There is a possibility that trains will run as diesel railcars from Shinjo Station to Akita Station, but since electric railcars are available on the section from Innai Station to Akita Station, it would be inefficient to use diesel railcars. Therefore, it is unlikely that the same number of trains as before the disaster (7 round trips per day) will run to Akita Station. It is expected that the operation of trains that run through the affected section will change significantly from before the disaster.
Predicted operation format after resumption of service in 2025
When service resumes, the diesel railcars will likely be deployed mainly on sections that can only be served by diesel railcars, namely the non-electrified section between Shinjo Station and Innai Station. However, if all diesel railcars turn back at Innai Station toward Shinjo Station, it would be inconvenient for passengers traveling from Shinjo to Yuzawa Station in the center of Yuzawa City, requiring a transfer. If complaints arise from users and local governments along the line about this inconvenience, diesel railcar service may be extended to Yuzawa Station. Innai Station is 16.0 km from Yuzawa Station. Personally, I think it would be nice to extend the distance. Also, even if not to Akita Station, I think it would be good to have direct trains at least to Yokote Station, which connects to 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 a plan to remove power facilities from local lines in 2021. If the Ou Main Line example proves successful, I think there's a chance that power facilities will be removed on other lines in the future (the Ou Main Line's section between Innai Station and Omagari Station, and the narrow-gauge line between Omagari Station and Akita Station are also likely candidates). From a hobbyist's perspective, it's a little sad to see lines that once carried long-distance express trains go unelectrified, but I sincerely hope that this will have a positive impact on maintaining local lines in the future.
![National Fireworks Competition (Omagari Fireworks)](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAJYAAACWAQAAAAAUekxPAAAAAnRSTlMAAHaTzTgAAAAaSURBVEjH7cExAQAAAMKg9U9tDQ+gAACAdwMLuAABXZHjmQAAAABJRU5ErkJggg== "[Daisen City, Akita Prefecture] Omagari Fireworks is one of the "Three Greatest Fireworks Festivals in Japan"! Enjoy the works of fireworks makers who put their reputations on the line")
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