Mizushima Main Line

The line began life as a wartime industrial railway. On 17 September 1942 a licence was granted for a dedicated railway, and on 30 June 1943 it opened as a private works line of the Mitsubishi Heavy Industries Mizushima Aircraft Factory, running between Kurashiki and the aircraft plant to move materials and workers. After the war the railway and the surrounding land passed in 1947 to the Mizushima Industrial City Development company, and the route was reborn for public use: on 20 August 1948 it opened as a local railway under the Local Railway Law, running from Kurashiki Station (today's Kurashiki-shi Station) to Mizushima and on to Mizushima-kō (Mizushima Port).

In the 1950s the line came under municipal control. On 1 April 1952 it was transferred to the city of Kurashiki and operated thereafter by the Kurashiki City Transportation Bureau as a municipal railway. The surrounding Mizushima district, designated for heavy industry, grew rapidly into one of western Japan's major coastal industrial complexes, and the railway expanded to serve it: a branch to Saidaiba (Saitō Pier) opened on 1 July 1962, and a line toward the Kawasaki Steel works at Kawatetsu-mae opened on 20 August 1965, reflecting the line's deepening role as an industrial carrier.

The modern operator was created to take the railway off the city's books. The Mizushima Rinkai Railway was established on 2 February 1970 as a joint venture of Japanese National Railways and the city of Kurashiki, and on 1 April 1970 it took over all of the lines from the Kurashiki City Transportation Bureau. Under the new company the line was modernised step by step: centralised traffic control was introduced between Kurashiki-shi and Mizushima on 1 June 1971, and on 17 September 1972 passenger service was extended from Mizushima to a new terminus at Mitsubishi Jidōsha-mae, beside the Mitsubishi Motors plant, fixing the present passenger route between Kurashiki-shi and Mitsubishi Jidōsha-mae.

Freight has always been central to the line, and in 1983 it was reorganised around a new hub. On 1 April 1983 the Kurashiki Freight Terminal opened between Mitsubishi Jidōsha-mae and Kawatetsu-mae, and on the same day freight service on several outer sections — toward Kawatetsu-mae and on the Mizushima-kō and Saidaiba branches — was discontinued, concentrating freight on the new terminal. The railway carries containers and bulk goods from the Mizushima industrial complex and exchanges through freight with the Japan Freight Railway Company (JR Freight) network via Okayama; from 1984 it even ran its own distinctive private containers. JR Freight became a part-owner of the company, holding about 35 percent of its shares, reflecting how closely the line is tied to the national freight system.

Through the 1980s and 1990s the passenger railway was steadily upgraded and the line settled into its present form. Kurashiki-shi Station was relocated in front of JR's Kurashiki Station on 7 April 1981; new intermediate stations were added through the decade; and on 7 September 1992 the section between Urata and Mitsubishi Jidōsha-mae was elevated, opening Tokiwa Station. Automatic train stop was installed in 1995, and one-man operation began on 16 March 1996, expanding to almost all trains by 2002. Station numbering was introduced in 2019. Today the Mizushima Main Line remains a compact but busy mixed-traffic railway, moving commuters and students between central Kurashiki and the coast while serving as a freight artery for one of Japan's largest industrial zones.

• 194217 September: a licence is granted for a dedicated (works) railway.
• 194330 June: the line opens as a private works railway of the Mitsubishi Heavy Industries Mizushima Aircraft Factory, between Kurashiki and the aircraft plant.
• 1947The railway is transferred from the former aircraft factory to the Mizushima Industrial City Development company.
• 194820 August: reopens as a local railway under the Local Railway Law, from Kurashiki Station (now Kurashiki-shi) via Mizushima to Mizushima-kō (Mizushima Port).
• 19521 April: the line is transferred to the city of Kurashiki and run by the Kurashiki City Transportation Bureau as a municipal railway.
• 19621 July: a branch to Saidaiba (Saitō Pier) opens.
• 196520 August: a line toward the Kawasaki Steel works at Kawatetsu-mae opens.
• 19702 February: the Mizushima Rinkai Railway is established by Japanese National Railways and the city of Kurashiki; on 1 April it takes over all the lines from the Kurashiki City Transportation Bureau.
• 19711 June: centralised traffic control (CTC) is introduced between Kurashiki-shi and Mizushima.
• 197217 September: passenger service is extended from Mizushima to Mitsubishi Jidōsha-mae, which opens as the new passenger terminus.
• 19817 April: Kurashiki-shi Station is relocated in front of JR's Kurashiki Station.
• 19831 April: the Kurashiki Freight Terminal opens between Mitsubishi Jidōsha-mae and Kawatetsu-mae; freight on the Kawatetsu-mae section and the Mizushima-kō / Saidaiba branches is discontinued, concentrating freight on the new terminal.
• 19927 September: the Urata–Mitsubishi Jidōsha-mae section is elevated and Tokiwa Station opens.
• 199616 March: one-man operation begins; it expands to almost all weekday and holiday trains by 2002.