Hidaka Main Line

The line began as an industrial railway rather than a state project. From 1909 the trading house Mitsui & Co. operated a horse-drawn freight tramway between Tomakomai and Mukawa to carry timber for the Oji Paper mill at Tomakomai, and the operation was later converted to steam. In 1913 the business was reorganised as the Tomakomai Light Railway, which on 1 October 1913 opened a 762 mm narrow-gauge line from Tomakomai to Saruta (the present Tomikawa). With backing from Oji Paper, a second company, the Hidaka Development Railway, extended the route further east in the 1920s, reaching Atsuga in 1924 and Shizunai in 1926, also in 762 mm gauge.

On 1 August 1927 the government bought out both the Tomakomai Light Railway and the Hidaka Development Railway, and the nationalised Tomakomai–Shizunai route was designated the Hidaka Line. The Japanese Government Railways then regauged the light-railway track to the national 1,067 mm standard, converting Tomakomai–Saruta on 26 November 1929 and Saruta–Shizunai on 10 November 1931, so that through running with the rest of the network became possible.

The state pushed the railway on down the coast in stages: it was extended to Hidaka-Mitsuishi on 15 December 1933, to Urakawa on 24 October 1935, and finally to Samani on 10 August 1937, completing the full 146.5 km route. On 1 November 1943 the line was renamed the Hidaka Main Line, when the new Tomiuchi Line branched off from it at Mukawa. Steam gave way to diesel railcars through the 1950s, with full dieselisation completed on 1 October 1957.

When Japanese National Railways was broken up and privatised on 1 April 1987, the Hidaka Main Line passed to the newly formed JR Hokkaido. Running for kilometre after kilometre along an exposed, eroding shoreline, the line was chronically vulnerable to natural disasters, and its history is punctuated by repeated suspensions caused by earthquakes, heavy rain, typhoons and high seas that washed away embankments and bridges. As a lightly used rural route, each such closure was harder to justify repairing than the last.

The decisive blow came on 8 January 2015, when high waves washed out the roadbed near Atsuga, around the 67.5 km point, and severed the Mukawa–Samani section. Services beyond Mukawa were suspended indefinitely and replaced by substitute buses, and further storms over the following two years — including Typhoon No. 17 in September 2015 and a run of typhoons in August 2016 — inflicted still more damage on the dormant track and its structures.

JR Hokkaido concluded that reopening was not viable. By November 2016 the company estimated that restoring the line would cost about 8.6 billion yen, with a further annual burden of roughly 1.34 billion yen to keep it running, and on 15 December 2016 it announced that it would give up on rail restoration of at least the Hidaka-Mombetsu–Samani section in favour of conversion to buses. After years of negotiation, JR and the seven affected coastal towns agreed on closure, and on 1 April 2021 the 116.0 km Mukawa–Samani section was formally abolished and permanently replaced by bus services.

What remains of the Hidaka Main Line today is only its original inland stretch, the 30.5 km from Tomakomai to Mukawa, served by a handful of local trains calling at four stations. The long coastal line that once linked the towns of the Hidaka district to the rail network survives only as a bus corridor, and the surviving rail section is among the short, isolated branches whose long-term future JR Hokkaido has flagged as difficult to sustain.

• 19131 October: the Tomakomai Light Railway opens a 762 mm gauge line from Tomakomai to Saruta (present-day Tomikawa).
• 19246 September: the Hidaka Development Railway extends the line from Saruta to Atsuga (762 mm gauge).
• 19267 December: the Hidaka Development Railway extends the line to Shizunai.
• 19271 August: the government buys out both private companies; the nationalised Tomakomai–Shizunai route is designated the Hidaka Line.
• 192926 November: the Tomakomai–Saruta section is regauged from 762 mm to the 1,067 mm national standard.
• 193110 November: the Saruta–Shizunai section is regauged to 1,067 mm.
• 193315 December: the line is extended from Shizunai to Hidaka-Mitsuishi.
• 193524 October: the line is extended to Urakawa.
• 193710 August: the line is extended to Samani, completing the full 146.5 km route.
• 19431 November: the line is renamed the Hidaka Main Line, as the new Tomiuchi Line branches off from it at Mukawa.
• 19571 October: dieselisation of the line is completed.
• 19871 April: with the privatisation of Japanese National Railways, the line passes to JR Hokkaido.
• 20158 January: high waves wash out the roadbed near Atsuga (about the 67.5 km point), severing the Mukawa–Samani section, which is suspended and replaced by substitute buses.
• 201615 December: JR Hokkaido, estimating restoration at about 8.6 billion yen plus roughly 1.34 billion yen a year to operate, announces it will abandon rail restoration of at least the Hidaka-Mombetsu–Samani section in favour of buses.
• 20211 April: the 116.0 km Mukawa–Samani section is formally abolished and permanently replaced by bus services, leaving only the 30.5 km Tomakomai–Mukawa section.