Meitetsu Mikawa Line

The line was built not by the state but by the Mikawa Railway (三河鉄道), which grew out of two light-railway ventures promoted from around 1910–1911 by politicians and notables of Kariya together with Osaka business interests — a coastal scheme linking Ōhama (now Hekinan) through Takahama to Chiryū via a connection with the government Tōkaidō line at Kariya, and an inland scheme from Chiryū to Koromo (now Toyota). The two were merged, and the Mikawa Railway was formally established on 30 May 1912, deciding at the outset to build to 1,067 mm gauge rather than the originally licensed 762 mm.

Construction began at the southern, coastal end. On 5 February 1914 the Mikawa Railway opened its first section, between Kariya-shin (now Kariya) and Ōhama-minato (now Hekinan); at the opening the line ran about 14.5 km and a one-way trip took over an hour. It was extended inland to the first-generation Chiryū in 1915, and pushed north thereafter, reaching Koromo (now Toyotashi) in 1920 and the line's southern–northern through section being completed when the Koshido–Sanage segment opened on 31 October 1924. In February 1926 the whole Ōhama-minato–Sanage line was electrified at 1,500 V DC, and from that point every later extension was built electrified.

The company then built outward beyond both present termini. North of Sanage, the line was extended in stages — Sanage to Edagawa and on to Mikawa Hirose in 1927, and Mikawa Hirose to Nishi Nakagane on 22 January 1928. South of the coast, the line was extended from Ōhama-minato to Kamiya (later Matsukijima) in 1926 and on to Mikawa Yoshida (now Kira-Yoshida) on 25 August 1928. The Mikawa Railway also pressed further southeast, completing the line on toward Gamagōri in 1936; that Mikawa Yoshida–Gamagōri stretch carried the Mikawa Line name until 1948, when it was separated as the Gamagōri Line.

The Mikawa Railway was absorbed into Nagoya Railroad on 1 June 1941. Under Meitetsu the through route between the coast and the hills was steadily integrated with the rest of the network: in February 1943 the Nishio Line's original Kira-Yoshida Station was relocated and merged into Mikawa Yoshida, tying the southern end of the line to the Nishio and Gamagōri lines. A planned roughly 8-kilometre extension onward from Nishi Nakagane to Asuke, begun in the 1930s and with most of its roadbed built, was never railed — the steel intended for its track was requisitioned for the war — and the project was formally abandoned when the licence lapsed on 27 June 1958.

The modern shape of the busy central section was set around Chiryū. The line crosses the Nagoya Main Line there in a switchback, and the present (third-generation) Chiryū Station opened on 1 April 1959, when the former Chiryū was split into Higashi-Chiryū on the main line and Mikawa Chiryū on the Mikawa Line and a new alignment was brought into use. It was after this 1950s reconfiguration that the line came to be operated in two halves divided at Chiryū, the basis of the Yamasen/Umisen distinction; when Meitetsu introduced station numbering in March 2016, the two halves were given separate codes (MY for the mountain side, MU for the sea side).

The far ends of the line did not survive the shift to road travel. Freight operations ended on 1 January 1984; faced with thin patronage, Meitetsu withdrew electric operation and switched to small diesel railbuses on the Nishi Nakagane–Sanage section from 14 March 1985 and on the Hekinan–Kira-Yoshida section from 1 July 1990. Ridership kept falling, and after years of subsidy negotiations with lineside municipalities both lightly used ends were closed on 1 April 2004 — the 8.6 km Nishi Nakagane–Sanage stretch in the north and the 16.4 km Hekinan–Kira-Yoshida stretch in the south — leaving the present Sanage–Hekinan line, which today carries dense commuter traffic through the Toyota industrial belt and along the coast at Takahama and Hekinan, with a recorded daily ridership of 73,556 in FY2003.

• 191230 May: the Mikawa Railway (三河鉄道) is formally established, merging two earlier light-railway ventures and deciding to build to 1,067 mm gauge rather than the licensed 762 mm.
• 19145 February: the first section opens, Kariya-shin (now Kariya) to Ōhama-minato (now Hekinan), about 14.5 km, with a one-way trip taking over an hour.
• 191528 October: the line is extended inland from the first-generation Chiryū to Kariya-shin, connecting Chiryū to the coastal section.
• 19201 November: the line reaches Koromo (now Toyotashi) with the Uwagoromo–Koromo segment, after Chiryū–Tsuchihashi and Tsuchihashi–Uwagoromo opened earlier the same year.
• 192431 October: the Koshido–Sanage segment opens, completing the through Sanage–Ōhama-minato operating section.
• 19265 February: the Ōhama-minato–Sanage line is electrified at 1,500 V DC; all subsequent extensions are built electrified.
• 192822 January: the northern extension reaches Nishi Nakagane (Mikawa Hirose–Nishi Nakagane), after the Sanage–Edagawa–Mikawa Hirose segments opened in 1927.
• 192825 August: the southern end is extended from Kamiya (later Matsukijima) to Mikawa Yoshida, the station that would later become Kira-Yoshida.
• 193610 November: the Mikawa Railway completes its line on toward Gamagōri (Mikawa Yoshida–Gamagōri); this stretch carried the Mikawa Line name until separated as the Gamagōri Line in 1948.
• 19411 June: the Mikawa Railway is absorbed into Nagoya Railroad (Meitetsu).
• 19431 February: the Nishio Line's original Kira-Yoshida Station is relocated and merged into Mikawa Yoshida, tying the line's southern end to the Nishio and Gamagōri lines.
• 195827 June: the licence for the never-completed ~8 km Nishi Nakagane–Asuke extension lapses and the project is abandoned; its roadbed had been largely built but the rails were requisitioned during the war.
• 19591 April: the present (third-generation) Chiryū Station opens; the old Chiryū is split into Higashi-Chiryū (main line) and Mikawa Chiryū (Mikawa Line) and a new switchback alignment comes into use.
• 19841 January: freight operations on the line cease.
• 198514 March: electric operation on the Nishi Nakagane–Sanage section is withdrawn and replaced by diesel railbuses, with one-man operation introduced.
• 19901 July: electric operation on the Hekinan–Kira-Yoshida section is withdrawn and replaced by diesel railbuses.
• 20041 April: both lightly used ends are closed — the 8.6 km Nishi Nakagane–Sanage section in the north and the 16.4 km Hekinan–Kira-Yoshida section in the south — leaving the present 39.8 km Sanage–Hekinan line.