Kamaishi Line

The route began life as a privately built narrow-gauge light railway. The Iwate Light Railway opened its first section, from Hanamaki to Tsuchisawa, on 25 October 1913, and built outward in short stages over the following two years — extending west from Tsuchisawa toward Iwanehashi and east through Tōno toward the mountains. These segments were laid to a narrow 762 mm gauge typical of Japanese light railways of the period.

The two halves were joined on 23 November 1915, when the Iwanehashi–Kashiwagidaira link opened and through running between Hanamaki and Sennintōge became possible. At Sennintōge the railway met rugged terrain: the gap onward to the iron-mining town of Kamaishi was bridged not by track but by a cableway, so freight and passengers had to transfer to reach the coast.

The Iwate Light Railway was bought out and nationalised on 1 August 1936, and the Hanamaki–Sennintōge route became the government-run Kamaishi Line. Under state ownership the line was progressively rebuilt to the standard Japanese 1,067 mm gauge: the Hanamaki–Kashiwagidaira section was regauged on 20 September 1943, and the Kashiwagidaira–Tōno section followed on 10 December 1949.

Meanwhile the coastal end was tackled from the Kamaishi side. On 11 October 1944 a freight line from Kamaishi to Rikuchū-Ōhashi opened as the Kamaishi East Line (釜石東線), and the older inland portion was renamed the Kamaishi West Line (釜石西線). Passenger services over the Kamaishi–Rikuchū-Ōhashi section began on 15 June 1945.

The through route was finally completed on 10 October 1950, when the Ashigase–Rikuchū-Ōhashi link opened and connected the eastern and western lines into a single 90.2-kilometre railway from Hanamaki to Kamaishi. With the new alignment in place the steep Ashigase–Sennintōge section was abandoned, and the combined route was named simply the Kamaishi Line. Steam haulage ended on 20 March 1967, when the line was fully dieselised.

With the breakup and privatisation of Japanese National Railways on 1 April 1987, the Kamaishi Line passed to the newly formed East Japan Railway Company, which has operated it ever since as a local route serving the towns of inland Iwate and the coast.

In the modern era the line became best known for steam tourism. From 12 April 2014 JR East ran the "SL Ginga" excursion train, hauled by the restored JNR Class C58 locomotive C58 239, mainly at weekends; the service evoked the line's Galaxy-Railroad theme until ageing of its passenger coaches forced its withdrawal on 11 June 2023. The line's sightseeing role then passed to a new train: on 23 December 2023 the "Hinabi (Hitabi)" tourist service, formed of HB-E300 series diesel hybrid cars, began operating.

• 191325 October: the privately built Iwate Light Railway opens its first 762 mm-gauge section, Hanamaki–Tsuchisawa.
• 191523 November: the Iwanehashi–Kashiwagidaira link opens, completing through running between Hanamaki and Sennintōge (65.4 km); a cableway, not track, continued on to the mines at Kamaishi.
• 19361 August: the Iwate Light Railway is bought out and nationalised; the Hanamaki–Sennintōge route becomes the government-run Kamaishi Line.
• 194320 September: the Hanamaki–Kashiwagidaira section is regauged from 762 mm to the standard 1,067 mm.
• 194411 October: a freight line from Kamaishi to Rikuchū-Ōhashi opens as the Kamaishi East Line; the inland portion is renamed the Kamaishi West Line.
• 194515 June: passenger services begin on the Kamaishi–Rikuchū-Ōhashi (Kamaishi East Line) section.
• 194910 December: the Kashiwagidaira–Tōno section is regauged from 762 mm to 1,067 mm.
• 195010 October: the Ashigase–Rikuchū-Ōhashi link opens, joining the east and west lines into the single 90.2 km Kamaishi Line from Hanamaki to Kamaishi; the steep Ashigase–Sennintōge section is abandoned.
• 196720 March: steam haulage ends and the line is fully dieselised.
• 19871 April: with the breakup and privatisation of Japanese National Railways, the Kamaishi Line passes to the East Japan Railway Company (JR East).
• 201412 April: the 'SL Ginga' steam excursion train begins running, mainly at weekends, hauled by the restored JNR Class C58 locomotive C58 239.
• 202311 June: the 'SL Ginga' service ends, owing to ageing of its passenger coaches.
• 202323 December: the 'Hinabi (Hitabi)' tourist train, formed of HB-E300 series diesel hybrid cars, begins operating on the line.