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Itaya Pass which stands on the border between Fukushima and Yamagata prefectures , is the location of JR East's Yamagata Shinkansen and Yamagata Line, officially known as the Ou Main Line. As the Yamagata Shinkansen Tsubasa currently runs on the Ou Main Line, it plays an important role connecting the Kanto region, Fukushima and various parts of the Tohoku region, but Itaya Pass has always been known as a difficult place to travel. We will introduce the history of the railway at Itaya Pass.
What is Itaya Pass?
Itaya Pass is one of the passes near the border between Yamagata and Fukushima prefectures, crossing the Ou Mountain Range. It connects the villages of Itaya and Osawa in Yonezawa City, Yamagata Prefecture. JR East's Ou Main Line crosses this pass, so trains heading from Fukushima Station to Yonezawa Station or Yamagata Station must pass through the pass. A road also passes through Itaya Pass, but it is off the main route connecting Fukushima City and Yonezawa City. The main routes, National Route 13 and the Tohoku Chuo Expressway, pass through Kuriko Pass, which is further north than Itaya Pass. For this reason, the term Itaya Pass is primarily associated with railways, and is sometimes referred to as being almost synonymous with the section of the Ou Main Line between Fukushima Station and Yonezawa Station.
The gradient of Itaya Pass is 38‰ (3.8%) at its steepest point This means that for every 1,000m of horizontal travel, the elevation changes by 38m. While a 3.8% gradient is not a big deal for a car, it is quite steep for a train. It is currently classified as JR main lines . The length of the gradient, with an average gradient of 33.0‰ continuing for approximately 22km also makes Itaya Pass a difficult spot. As it is located in the mountains, it is plagued by heavy snowfall in winter.
The Yamagata Shinkansen "Tsubasa" train running near Itaya Station
Opening of the railway through Itaya Pass
The railway between Fukushima Station and Yonezawa Station, which passes through Itaya Pass, opened in May 1899. Since this was during the Meiji period, steam locomotives were used as the power source for trains. The nearly 40 tunnels built into Itaya Pass posed a major problem for trains pulled by steam locomotives. Steam locomotives spew out large amounts of smoke, especially when going uphill, and this smoke caused discomfort to train crews and passengers in the tunnels .
Steam locomotives continued to operate trains for half a century, right up until the end of the war in 1949. A documentary film titled "Records of the Electrification of the Ou Line" shows crew members and passengers suffering from the smoke, and how, because there were so few trains, children who went to school at the foot of the mountains had to wait at the station until evening before getting a special ride on a freight train to go home to their homes in the mountains .
Another problem with using steam locomotives is that they are weak. Although steam locomotives look powerful as they spew smoke and make a loud noise, the tractive effort they can actually exert is inferior to that of electric locomotives. This low tractive effort directly leads to the difficulty of climbing mountain passes.
Four stations along the mountain pass - Akaiwa Station, Itaya Station, Toge Station, and Osawa Station - were switchback stations For operational safety, stations could not be built on steep slopes, so at these stations, flat land was secured beside the main line and platforms were built there. Trains had to change direction to enter or exit stations beside the main line, which had a major impact on train speed.
In addition, locomotives designed to pull trains on flat tracks alone cannot climb the steep gradient of Itaya Pass, so locomotives were assigned to assist trains passing through Itaya Pass by coupling them to them. In later years, these assisting locomotives were designed specifically for the Itaya Pass.
4110 class steam locomotive, a support locomotive for the Itaya Pass (from Wikipedia)
Serious problems such as the smoke from steam locomotives could not be ignored, so electrification work was planned at Itaya Pass early after the war, that is, the installation of equipment to supply electricity to trains so that electric locomotives could be used, and construction began in 1946
Electrification of Itaya Pass
The electrification work at Itaya Pass was extremely difficult, as there were no major roads nearby and the area was subject to heavy snowfall. Three years after construction began, in 1949, trains began operating using a 1,500V DC power source. DC electric locomotives such as the EF15, EF16, and EF64, which were developed for mountain routes, were introduced.
EF16 electric locomotive (photo by author)
Additionally, when steam locomotives were used, trains had to switch back and forth between the four stations even if they didn't stop at the stations. However, tracks for through trains that could pass through the stations was carried out in parallel with the electrification work, so through trains can now operate smoothly.
In 1961, the Kiha 80 series diesel railcars began operation of the "Tsubasa" limited express train (between Ueno Station and Akita Station), and in 1964 the "Yamabato" limited express train The Kiha 80 series diesel railcars are self-propelled vehicles that use diesel fuel, but these express trains still needed to be coupled with a helper locomotive when crossing Itaya Pass. The Kiha 181 series, the successor to the Kiha 80 series, was initially operated without a helper locomotive, but the load on the engine at Itaya Pass was so great that a helper locomotive was once again coupled. This once again reminds us how difficult Itaya Pass was.
Kiha 80 series diesel railcar
About 20 years have passed since DC electrification, and lines around Itaya Pass (such as the Tohoku Main Line) have been electrified with 50Hz/20,000V AC, so the electrification method at Itaya Pass was also changed to AC in 1968. The ED78 and EF71 electric locomotives, which were developed for AC-electrified mountain lines, were newly introduced. In addition to pulling local trains, these locomotives also pulled the sleeper express " Akebono " (between Ueno Station and Aomori Station, etc.). However, as long sleeper express trains in particular put a heavy load on the locomotives, two ED78 or EF71 cars were coupled together to pull trains at Itaya Pass.
The entire Ou Main Line was electrified in 1975. This prompted limited express trains such as the Tsubasa Pass to be operated by the 485 series electric trains, which were the representative limited express trains of the JNR era, and the attachment of auxiliary locomotives became unnecessary.
Limited express "Tsubasa" operated by 485 series electric train
Yamagata Shinkansen opens
In the 1980s, consideration began to be given to the mini-shinkansen, a concept in which Shinkansen trains would run directly on conventional lines. Based on this concept, direct trains were to run between the Ou Main Line and the Tohoku Shinkansen, which opened in 1982, via Fukushima Station. This is the current Yamagata Shinkansen .
Please take a look at this article which explains how the Yamagata Shinkansen came to be
The opening of the Yamagata Shinkansen was a major change for Itaya Pass, similar to the electrification of the 1940s. The gap between the two rails was widened from 1,067 mm to 1,435 mm, the same as the Tohoku Shinkansen, meaning that all trains that had previously crossed the Itaya Pass could no longer pass through. Express trains the 400 series "Tsubasa" ShinkansenTsubasa express train operated by the 485 series ), and local trains, which previously ran with electric locomotives towing passenger cars, were replaced with the 719 series. The 400 series was later replaced by the E3 series, and from 2024, replacement with the latest E8 series trains will begin.
The four switchback stations at Itaya Pass were a symbol of the pass's difficulty, but the switchbacks have now been eliminated at all stations. The platforms at the four stations have been moved from sidings to the main line, and they have become regular stations. Furthermore, Akaiwa Station, the only one of the four located within Fukushima Prefecture, was closed in 2021 due to depopulation around the station.
"Tsubasa" passing through Toge Station after the switchback is removed
As a child, I have fond memories of my father, who was born in Fukushima City, taking me on the Itaya Pass local trains with 50-series passenger cars before the switchbacks were removed, as well as the local trains and "Tsubasa" trains after the Yamagata Shinkansen opened. My memories of the ride before the switchbacks were removed are hazy, as I was still very young (and my father has since passed away, so there's no way to confirm), but I remember the train backing up into the station with the red passenger car at the front, and the train changing direction in a tunnel (?), so I'm sure it was a local train at Itaya Pass. It 's a fond memory for me, and I can still recall it in fragments, but I think my father probably went to ride it because he wanted to ride it more than anything else before the switchbacks at Itaya Pass were removed.
Itaya Pass is still a difficult pass
Since the Yamagata Shinkansen opened in 1992, the steep gradients of Itaya Pass have been easily traversed by the Shinkansen "Tsubasa" and local trains converted to electric trains. However, although it is no longer Itaya Pass remains a hazardous area due to its continuous sharp curves . Of the Yamagata Shinkansen train cancellations and delays due to rain, snow, collisions with animals, etc., 40% occur between Fukushima Station and Yonezawa Station, which includes Itaya Pass.
So, although it is unclear whether this will actually happen, there is a plan under consideration to eliminate this difficult section by digging a long tunnel of approximately 23 km under Itaya Pass. The tunnel construction will take 15 years and cost 150 billion yen, but it is expected to reduce the time it takes for the Tsubasa to cross the pass by over 10 minutes and improve the reliability of train operations, especially in winter. The key to realizing this plan will likely be whether the costs are deemed to be worth the benefits.
Touge no Chikaramochi
Toge Station, which was once one of the switchback stations, now has a street vendor selling "Toge no Chikara Mochi," a rare item sold nationwide. The product being sold is "Toge no Chikara Mochi," a daifuku mochi made by "Toge no Chaya," a shop located near Toge Station, and is made of pure white mochi wrapped in smooth bean paste.
The roads near Toge Station are rough, so while it's not impossible to visit by car, it is quite difficult. Furthermore, the Yamagata Shinkansen's Tsubasa does not stop at Toge Station, and only six local trains stop there each day, making it difficult to visit by train either. However, the sight of street vendors and the deliciousness of Toge no Chikara Mochi (rice cakes eaten on the road) have made it a specialty of Itaya Pass, both in the past and now.
Itaya Pass is said to be one of the three steepest sections of railway in Japan, along with Usui Pass (now closed) on the Shinetsu Main Line, which was on the border Senohachigoe . As we have seen in this article, how people have struggled with this difficult section, and how it remains a difficult section today. When you cross Itaya Pass on the Tsubasa train, take in the scenery passing by the window. You will get a glimpse of the harshness of nature and the history of the Ou Main Line's struggle with it.
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