The
Japanese Government Railways opened the Takasaki to Yokokawa section in 1885, the Naoetsu to Sekiyama section the following year, and the Sekiyama–Nagano–Karuizawa section in 1888. In order to surmount the 552 metre altitude difference between Yokokawa and Karuizawa (which are apart), it then constructed an
Abt rack section through the
Usui Pass, which opened in 1893, and was double-tracked for from Karuizawa to the top of the rack section. A horse-drawn tramway operated between Yokokawa and Karuizawa until the rack section opened. The Hokuetsu Railway opened the Naoetsu to Nagaoka section in 1897, extending the line to Niigata in 1904. That company was nationalised in 1907. In 1909, the Imperial Japanese Railway authorities invited bids for the electrification of the route. A German company was selected to provide the engines and
General Electric supplied the turbines at the power station. In 1912, the rack section was electrified using
third rail at 600 V DC, this being the first use of this method in Japan. The electrification allowed for the use of faster and longer trains which reduced journey times and also pollution from the steam engines. A link to archival footage of the rack section operation is available here
Double-tracking The Karuizawa to Nagano section was double-tracked between 1917 and 1920, with the Nagaoka to Miyauchi section double-tracked in 1931, and the Niitsu–Kamo section in 1944. Double-tracking of the remainder of the Niigata to Naoetsu line was undertaken in sections between 1958 and 1973. Double-tracking of the remainder of the Takasaki to Kaminagano line was undertaken in sections between 1963 and 1973, commencing with the replacement of the rack mechanism with an adhesion only electrified (1,500 V DC
catenary) operation on the 1 in 15 (6.7%) grade. The rack equipment was initially kept as a contingency, and removed two months after the adhesion-only operation commenced and had proved its reliability. The Kurohime to Myoko-Kogen section was double-tracked in conjunction with a realignment in 1980. The Mure to Kurohime section was also realigned and prepared for double-tracking (including new double-track size tunnels), but the second track was not laid.
Electrification The Miyauchi to Nagaoka section was electrified in 1947 at 1,500 V DC in conjunction with the electrification of the
Joetsu Line, with the Nagaoka to Niigata section electrified in 1962, the same year the Takasaki to Yokokawa section was commissioned to facilitate the extension to Nagano the following year via the new adhesion line through the Usui Pass mentioned above. The Nagano to Naoetsu section was electrified in 1966, and extended to Miyauchi in 1969.
Separation into sections In 1997, following the opening of the
Nagano Shinkansen, the Yokokawa to Karuizawa section was closed, and the Karuizawa to Shinonoi section transferred to the
third-sector Shinano Railway. On 14 March 2015, following the extension of the
Hokuriku Shinkansen to , the to section was also spun off to the following two third-sector operating companies owned primarily by the respective prefectures and municipalities. •
Shinano Railway Kita-Shinano Line (37.3 km, to ) •
Echigo Tokimeki Railway Myōkō Haneuma Line (37.7 km, Myōkō-Kōgen to )
Station numbering Station numbering was introduced on the Shinonoi–Nagano section from February 2025, with Shinonoi station being assigned SE09. Numbers increase towards Nagano.
Former connecting lines (Note - for the connections at stations between Karuizawa and Shinonoi, see
Shinano Railway Line) • Nagano Station: The Zenkoji Hakuba Railway Co. opened a line to Susohana Guchi in 1936. A proposal for the line to be extended to Hakuba on the
Oito Line did not eventuate, and the line closed in 1944. • Kuroi Station: The Kubiki Railway Co. opened a gauge line to Uragawara between 1914 and 1916, with the line closing in 1971. • Raikoji Station: The Nagaoka Railway Co. opened a line to Teradomari (on the
Echigo Line) between 1915 and 1921. This company introduced Japan's first diesel railcar in 1928, and in 1951 electrified of the line at 750 V DC in 70 days, completing the balance the following year. Significant typhoon damage occurred in 1966, and in 1972, passenger services ceased between Raikoji and Nishinagaoka, with the entire line becoming freight-only three years later. The line closed in 1995. :The 13 km gauge Uonuma Railway to Nishiojiya was opened in 1911, and nationalised in 1922. It was converted to gauge in 1954, freight services ceased in 1960, and the line closed in 1984. • Nagaoka Station: The Tochio Railway opened a 27 km gauge line to Tochio and Yūkyūzan between 1915 and 1924. The line was electrified at 600 V DC in 1948, with this being raised to 750 V DC in 1956. CTC signalling was commissioned in 1961, freight services ceased in 1967, and the line closed between 1973 and 1975. • Higashi Sanjo Station: The Echigo Railway Co. opened the 8 km line to Echigo Nagasawa in 1927, and was nationalised two months later. Freight services ceased in 1960, and the line closed in 1985. • Kamo Station: The Kanbara Railway Co. operated a line to Gosen on the
Ban'etsu West Line from 1923 until 2002. ==References==