History
Ainonai Station opened on 18 November 1912 as Kami-Ainonai on the Yūbetsu Light Railway between Notsukeushi (now Kitami) and Rubeshibe. The line was regauged from 762 mm to 1,067 mm on 7 November 1916 and after several renamings joined the Sekihoku Main Line on 1 April 1961. On 5 February 1934 the station was renamed Ainonai (2nd) when the original Ainonai became Higashi-Ainonai. Freight handling outside an industrial spur ended on 1 October 1969, and JR Hokkaido inherited the station at the 1987 privatisation, after which full unstaffing followed on 1 April 1992. The depot was rebuilt in 1988, the kanji simplified to 相内 in 1997, and platforms extended in April 2004 to end door-cuts on regular trains.
History summarized from Japanese & English Wikipedia · last reviewed 2026-05-18.
Notes
Until April 2004 the platform was too short for the regular train sets, so doors on overhanging carriages had to be locked closed — a practice known as 'door-cut' service.