Astram Line

Plans for a new transit system connecting the centre of Hiroshima with the rapidly growing suburbs to the north-west were first proposed in July 1977. The third-sector operating company, Hiroshima Rapid Transit, was established in 1987 to build and run the line. In 1988 the company concluded a three-party agreement with the area's bus operators and applied for the track licences for the route, which were granted that August; the application covered the central Hondōri–Kenchō-mae section and the Kenchō-mae–Chōrakuji section toward the planned depot.

The groundbreaking ceremony and the start of construction took place on 28 February 1989. In October 1990 the company applied for the track licence for the outer Chōrakuji–Kōiki-kōen section, which was granted the following March, extending the project out to what would become the line's northern terminus.

Construction was overshadowed by a major accident. On 14 March 1991 a girder being erected on the elevated viaduct collapsed near the construction site of Kamiyasu Station, killing 15 people and injuring 8 — an event recorded as the Hiroshima New Transit System girder-collapse accident, one of the worst construction disasters in the building of a Japanese railway. Work resumed in stages: the underground portion restarted within days, other sections by mid-year, the outer Chōrakuji–Kōiki-kōen segment from October 1991, and the accident site itself around December 1991.

After opening inspections were completed in July 1994 and local preview rides were held that August, the whole line from Hondōri to Kōiki-kōen-mae — all 18.4 km and, at opening, 21 stations — entered revenue service simultaneously on 20 August 1994. The timing was deliberate: the line was built as access infrastructure for the 1994 Asian Games held in Hiroshima that October, carrying spectators to the main stadium, the Hiroshima Big Arch, beside the northern terminus at Kōiki-kōen-mae.

In its first decades the line refined its operations rather than its route. Express trains were introduced in a March 1999 timetable revision, with timed express/local connections added at Ōmachi from 2000; the express services were later wound back, with the holiday-timetable expresses dropped in 2003 and the weekday expresses in 2004. The line adopted the PASPY IC fare card on 8 August 2009, also accepting ICOCA, and joined the nationwide mutual IC-card service in March 2018.

The network's one route change came on 14 March 2015, when Shin-Hakushima Station opened as an infill stop between Hakushima and Jōhoku to provide a transfer with the JR Sanyō Main Line, bringing the line to its present 22 stations; that June the company announced plans to study a "Saifū Toshi Line" extension from Kōiki-kōen-mae toward JR Nishi-Hiroshima. The original 6000 series cars, which had run since the 1994 opening, gave way to the new 7000 series — introduced into service on 26 March 2020 — and the 6000 series made its final run on 18 May 2025.

• 1977July: a new transit system linking central Hiroshima with the north-western suburbs is first proposed.
• 1987The third-sector company Hiroshima Rapid Transit is founded to build and operate the line.
• 1988A three-party agreement is concluded with area bus operators; the track licences for the Hondōri–Kenchō-mae and Kenchō-mae–Chōrakuji sections are applied for and granted in August.
• 198928 February: groundbreaking ceremony and start of construction.
• 19908 October: the company applies for the track licence for the outer Chōrakuji–Kōiki-kōen section (granted March 1991).
• 199114 March: a girder being erected collapses near the Kamiyasu Station construction site, killing 15 and injuring 8 (the Hiroshima New Transit System girder-collapse accident); construction later resumes in stages.
• 199420 August: the whole Hondōri–Kōiki-kōen-mae line (18.4 km, 21 stations at opening) enters revenue service simultaneously, built as access for the 1994 Asian Games and serving the Hiroshima Big Arch stadium.
• 199920 March: a timetable revision introduces express trains.
• 200420 March: the last weekday express trains are discontinued (holiday expresses had ended in 2003).
• 20098 August: the PASPY IC fare card is introduced, with ICOCA also accepted.
• 201514 March: Shin-Hakushima Station opens as an infill stop between Hakushima and Jōhoku, giving a transfer with the JR Sanyō Main Line and bringing the line to 22 stations.
• 202026 March: the new 7000 series cars enter service, beginning the replacement of the original 6000 series (whose final run was 18 May 2025).