Tazawako Line

The name of the East Japan Railway Company's track that runs from Iwate Prefecture to the central part of Akita Prefecture. The line is 75.6 km long between Morioka and Omagari. The entire line is single track and AC electrified. It crosses the Ou Mountains to connect the Tohoku Main Line and the Ou Main Line. It runs through the Shizukuishi River basin, a tributary of the Kitakami River, and the Tamagawa River basin, a tributary of the Omono River, and passes through the watershed through the Sengan Tunnel (3,915 meters long). The section closer to Morioka was constructed as the Hashiba (light) Line, and the section closer to Omagari as the Obonai (light) Line, the former opened between Morioka and Hashiba from 1921 to 1922 (the Shizukuishi-Hashiba section was suspended in 1944), and the latter opened between Omagari and Obonai (now Tazawako) from 1921 to 1923, but from 1964 to 1966 (Showa 39 to 41) it connected Shizukuishi and Obonai, and the two lines were integrated to form the Tazawako Line. It was electrified in 1982, and express trains connecting to the Tohoku Shinkansen began to run between Morioka and Akita, becoming equivalent to a main line railway.

In 1987, following the privatization of the Japanese National Railways, it became part of the East Japan Railway Company. In March 1997, the Akita Shinkansen, a mini-shinkansen train, began commercial operation. As a result, the Tazawako Line was converted from a 1,067mm gauge to a 1,435mm gauge. Conventional trains are no longer allowed on the line, but local trains between Morioka and Omagari have been modified to fit the new gauge. Along the line are Lake Tazawa and Kakunodate, which retains the atmosphere of a small castle town.

[Eiichi Aoki and Ryo Aoki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

岩手県から秋田県の中央部を走る東日本旅客鉄道の線路名称。盛岡―大曲(おおまがり)間75.6キロメートル。全線単線、交流電化。奥羽山脈を横断して東北本線と奥羽本線を結ぶ。北上(きたかみ)川の支流雫石(しずくいし)川流域と雄物(おもの)川の支流玉川の流域を走り、分水嶺(ぶんすいれい)を仙岩(せんがん)トンネル（長さ3915メートル）で抜ける。盛岡寄りは橋場(はしば)（軽便）線、大曲寄りは生保内(おぼない)（軽便）線として建設され、前者は1921～1922年（大正10～11）盛岡―橋場間を（1944年、雫石―橋場間休止）、後者は1921～1923年大曲―生保内（現、田沢湖）間を開業したが、1964～1966年（昭和39～41）雫石―生保内間を結び、両線を統合して田沢湖線とした。1982年電化され、盛岡―秋田間に東北新幹線に接続する特急列車が走るようになって、幹線鉄道に準ずるものとなった。

　1987年、日本国有鉄道の分割民営化に伴い、東日本旅客鉄道に所属。1997年（平成9）3月、ミニ新幹線方式の秋田新幹線の営業運転が開始された。それに伴い、田沢湖線は全線軌間1067ミリメートルから1435ミリメートルに改軌された。在来車両の乗入れはできないが、盛岡―大曲間の普通列車は車両を新軌間に合わせて改造し運行している。沿線には田沢湖や小城下町の趣(おもむき)を残す角館(かくのだて)などがある。

［青木栄一・青木　亮］

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