Chikuhi Line

The line began as a private venture by the Kita-Kyushu Railway, which set out to build a route between Hakata and Imari. The first segment, between Fukuoka and Hamasaki, opened on 5 December 1923, and over the following years the company extended the line in both directions. It reached Maebaru in 1924, pushed on to Higashi-Karatsu (then sited near the Matsuura River, on the opposite bank from the Karatsu Line) and toward Meinohama in 1925, and arrived at Hakata in 1926. In 1929 the line was extended from Higashi-Karatsu to Yamamoto, where it junctioned with the Karatsu Line; because of the local topography, Higashi-Karatsu became a switchback (reversing) station in the process.

The route was completed on 1 March 1935 when the Yamamoto–Imari section opened, giving a continuous railway from Hakata through Karatsu to Imari. The Kita-Kyushu Railway's finances had deteriorated, however, and on 1 October 1937 the company was bought out and nationalised; the Japanese Government Railways designated the through route the Chikuhi Line, then 86.1 km long, and renamed many of its stations. For the next several decades it remained a non-electrified local line, worked by steam and later diesel traction; regular steam-hauled passenger services lasted until 1969.

The line's character was transformed on 22 March 1983, when the opening of the Fukuoka City Subway's Airport Line allowed through running into central Fukuoka. On that single day the Chikuhi Line was reorganised end to end. The Hakata–Meinohama section, which paralleled the new subway, was abandoned (11.7 km), as was the Nijinomatsubara–Yamamoto section (10.4 km) around Karatsu. A new line was opened from Karatsu to Nijinomatsubara (5.1 km), built using the elevated structure that had been intended for the never-completed Yobuko Line and including a relocated Higashi-Karatsu station together with new Watada station. The Meinohama–Karatsu section was electrified at 1,500 V DC to permit through running to Fukuoka via the subway, and 103-1500 series electric trains entered service. These changes left the line in the two disconnected pieces that exist today.

Ownership passed from the state to the private sector on 1 April 1987, when the Japanese National Railways were divided and privatised and the Chikuhi Line was inherited by JR Kyushu. With the change, the line's two parts were thereafter shown separately as Meinohama–Karatsu (42.6 km) and Yamamoto–Imari (25.7 km), and the previous overlap with the Karatsu Line between Yamamoto and Karatsu was resolved in the route description. Under JR Kyushu the busy eastern section was steadily upgraded: rapid services were introduced in 1990, the Shimoyamato–Chikuzen-Maebaru stretch was progressively double-tracked through to 2000, and new commuter trains arrived, the 303 series in 2000 and the 305 series in 2015.

The eastern section has become a heavily used suburban commuter artery for the Fukuoka conurbation, carrying frequent through services to and from Fukuoka Airport over the subway and dense traffic between Meinohama and Chikuzen-Maebaru. The lightly used western section between Yamamoto and Imari, by contrast, is a rural single-track line worked by diesel railcars, with only a handful of trains in each direction; at Imari it meets the Matsuura Railway's Nishi-Kyushu Line, though through services that once linked the Chikuhi Line with the former Matsuura Line via Imari no longer run. In July 2018 the line was hit by the heavy rains of that month, when a six-car train was derailed by a landslide between Shikaka and Hamasaki and several sections were closed for a few days before reopening.

• 19235 December: the Kita-Kyushu Railway opens its first segment, Fukuyoshi–Hamasaki.
• 19241 April: the line is extended from Maebaru to Fukuyoshi; further extended Hamasaki–Nijinomatsubara on 7 July.
• 192515 April: Meinohama–Maebaru opens; on 15 June the line is extended to Meinohama on the Fukuoka side and from Nijinomatsubara to (the original) Higashi-Karatsu.
• 192615 October: the line reaches Hakata, completing the Hakata-end extension.
• 19291 April: Higashi-Karatsu–Yamamoto opens, junctioning with the Karatsu Line at Yamamoto; Higashi-Karatsu becomes a switchback station.
• 19351 March: the Yamamoto–Imari section opens, completing the through route from Hakata to Imari.
• 19371 October: the Kita-Kyushu Railway is bought out and nationalised; Japanese Government Railways designate the route the Chikuhi Line (86.1 km) and rename many stations.
• 19621 August: the semi-express 'Kujūkushima' is introduced, running Hakata–Sasebo via the Chikuhi and Matsuura lines.
• 196916 March: regular steam-hauled passenger train operation ends on the line.
• 198322 March: with the Fukuoka City Subway Airport Line opening, the Hakata–Meinohama (11.7 km) and Nijinomatsubara–Yamamoto (10.4 km) sections are abandoned; a new Karatsu–Nijinomatsubara line (5.1 km) opens; Meinohama–Karatsu is electrified at 1,500 V DC; through running with the subway begins and 103-1500 series trains enter service.
• 198620 July: the Meinohama–Shimoyamato section is double-tracked and Shimoyamato Station opens.
• 19871 April: with the division and privatisation of Japanese National Railways, the Chikuhi Line is inherited by JR Kyushu; its parts are shown as Meinohama–Karatsu (42.6 km) and Yamamoto–Imari (25.7 km) and the overlap with the Karatsu Line is resolved.
• 19906 October: rapid services are introduced on the Meinohama–Karatsu section (rapid running between Chikuzen-Maebaru and Karatsu).
• 200022 January: the 303 series EMU enters service; the Shimoyamato–Chikuzen-Maebaru double-tracking is completed.
• 20155 February: the 305 series EMU enters service on the Meinohama–Karatsu section.
• 20186 July: heavy rains cause a landslide that derails a six-car train between Shikaka and Hamasaki; affected sections close for a few days before reopening (Chikuzen-Maebaru–Karatsu on 11 July, Yamamoto–Imari on 12 July).