Miyazu Line

The line was built by the state rather than a private company. Local campaigners who had pressed for a railway concluded that private construction and operation would be too difficult and turned to lobbying for a government-built line; following this, the 1918 Imperial Diet approved a construction budget for a Mineyama Line (峰山線) linking Maizuru (the present Nishi-Maizuru) with Mineyama. The original alignment was to cross the Yura River at Shidaka and run down its left bank, but residents upstream feared a bridge would obstruct the flow and cause flooding, so after re-surveying the plan was changed in July 1921 to follow the right bank down to Kanzaki and cross the Yura River near its mouth.

Construction proceeded from the Maizuru end. The first section, from Maizuru (now Nishi-Maizuru) to Miyazu — a distance of 15.5 miles, about 24.94 km — was opened by the Ministry of Railways (Tetsudōshō) on 12 April 1924 as the Miyazu Line, with intermediate stations at Shisho, Shinonome, Tango-Yura, Kurida and Miyazu. The line was then extended westward in stages: to Tango-Yamada (the present Yosano) on 31 July 1925, to Mineyama on 3 November 1925, and to Amino on 25 December 1926.

The newly opened railway was struck almost at once by disaster. On 7 March 1927 the North Tango earthquake (magnitude 7.3), centred on Mineyama and Amino and killing some 2,925 people, severed the Maizuru–Amino section. Repairs were swift, and the line carried relief supplies and personnel: service reached Amanohashidate on the 8th, Tango-Yamada on the 9th, and the Amino–Kuchiōno section on the 14th, with full restoration on 21 March.

The western half of the route was built separately as the Minetoyo Line (峰豊線), worked from the Toyooka end. The Toyooka–Kumihama section opened on 15 December 1929, and the Amino–Tango-Kizu section followed on 25 May 1931. On 10 August 1932 the final gap, Tango-Kizu to Kumihama, was closed; the Minetoyo Line was completed and merged into the Miyazu Line, so that the whole Maizuru–Toyooka route became the Miyazu Line. Maizuru Station was renamed Nishi-Maizuru on 1 April 1944.

For decades the line was run by the national railways — the Ministry of Railways and then Japanese National Railways, to which it passed on 1 June 1949. It was the last line in Kyoto Prefecture to use steam locomotives, whose operations ended on 1 October 1972. As JNR's finances deteriorated, the line was designated a Specified Local Line (third batch) under the 1980 JNR Reconstruction Act, marking it for conversion away from national operation. Freight services ended on 14 March 1985, and on 1 April 1987 the JNR privatisation transferred the line to West Japan Railway (JR West).

The planned third-sector takeover followed. Miyafuku Railway — set up to take over the partly built Miyafuku Line — was renamed Kitakinki Tango Railway in 1989, and on 1 April 1990 it assumed operation of the Miyazu Line. With the change the operating length was revised from 84.0 km to 83.6 km, Tango-Yamada Station was renamed Nodagawa and Tango-Kizu became Kizu-Onsen, and the Tango Explorer limited express began running. The Miyazu Line was among the very last Specified Local Lines to remain under JR operation, transferring on the same day as the Kajiya and Taisha lines and completing the nationwide conversion programme. In connection with the electrification and speed-up of the Miyafuku Line, the Miyazu–Amanohashidate section was electrified at 1,500 V DC and upgraded for higher speeds on 16 March 1996, allowing through electric limited expresses such as the "Hashidate" and "Monju" to reach Amanohashidate from Kyoto and Osaka.

Faced with mounting deficits from depopulation, rising car use and competition from extended expressways — with the fall in passengers especially marked on the Amanohashidate–Toyooka side — Kyoto Prefecture, KTR's principal backer, opened a review with Hyōgo Prefecture and local authorities. A study group recommended a vertical-separation model, and on 1 April 2015 the operation of the railway was transferred from Kitakinki Tango Railway to WILLER TRAINS (Kyoto Tango Railway), a subsidiary of WILLER ALLIANCE. Under the new arrangement Kyoto Tango Railway became the Type-2 operator and Kitakinki Tango Railway the Type-3 owner, running the line by vertical separation; at the same time the line was given the nicknames Miyamai Line (Nishi-Maizuru–Miyazu) and Miyatoyo Line (Miyazu–Toyooka), line symbols and station numbers were introduced, and several stations were renamed, including Nodagawa to Yosano, Tango-Ōmiya to Kyō-Tango-Ōmiya, Kizu-Onsen to Yūhigaura-Kitsuonsen and Kabutoyama to Kabuto-yama.

• 192412 April: the Ministry of Railways (Tetsudōshō) opens the first section, Maizuru (now Nishi-Maizuru)–Miyazu (15.5 mi ≈ 24.94 km), as the Miyazu Line; Shisho, Shinonome, Tango-Yura, Kurida and Miyazu stations open.
• 192531 July: the line is extended from Miyazu to Tango-Yamada (the present Yosano), ~10.94 km; Amanohashidate, Iwatakiguchi and Tango-Yamada stations open.
• 19253 November: extended from Tango-Yamada to Mineyama, ~12.55 km; Kuchiōno (the present Kyō-Tango-Ōmiya) and Mineyama stations open.
• 192625 December: extended from Mineyama to Amino, ~7.24 km; Amino Station opens.
• 19277 March: the North Tango earthquake (M7.3), centred on Mineyama and Amino and killing ~2,925 people, severs the Maizuru–Amino section; it is fully restored by 21 March.
• 192915 December: the Toyooka–Kumihama section opens as the Minetoyo Line (~11.91 km); Tajima-Mie (the present Kōnotori-no-Sato) and Kumihama stations open.
• 193125 May: the Amino–Tango-Kizu section opens (5.6 km); Tango-Kizu (the present Yūhigaura-Kitsuonsen) Station opens.
• 193210 August: the final Tango-Kizu–Kumihama section (10.8 km) opens, completing the Minetoyo Line, which is merged in so that the whole Maizuru–Toyooka route becomes the Miyazu Line; Tango-Kanno (the present Shōtenkyō) Station opens.
• 19441 April: Maizuru Station is renamed Nishi-Maizuru.
• 19491 June: with the enactment of the Japanese National Railways Act, the line is transferred to Japanese National Railways (JNR).
• 19721 October: steam locomotive operation ends — the last in Kyoto Prefecture's JNR lines (JNR Class 9600 of the Nishi-Maizuru depot).
• 198514 March: freight services on the line cease.
• 19871 April: with the privatisation of JNR, the line is transferred to West Japan Railway (JR West); it had been designated a third-batch Specified Local Line under the 1980 JNR Reconstruction Act.
• 19901 April: operation passes to the third-sector Kitakinki Tango Railway (KTR); the operating length is revised 84.0→83.6 km, Tango-Yamada is renamed Nodagawa and Tango-Kizu becomes Kizu-Onsen, and the Tango Explorer limited express begins.
• 199616 March: the Miyazu–Amanohashidate section is electrified at 1,500 V DC and upgraded for higher speeds, enabling JR West electric limited expresses ('Hashidate', 'Monju') to reach Amanohashidate.
• 20151 April: the railway's operation is transferred from KTR to WILLER TRAINS (Kyoto Tango Railway) under a vertical-separation model — Kyoto Tango Railway as Type-2 operator, KTR as Type-3 owner; the line is branded the Miyamai Line (Nishi-Maizuru–Miyazu) and Miyatoyo Line (Miyazu–Toyooka) and several stations are renamed.