Abukuma Express Line

The line opened on 1 April 1968 as the Marumori Line (丸森線), operated by Japanese National Railways (JNR) between Tsukinoki and Marumori. It was originally planned as a bypass between Fukushima and Marumori to relieve congestion on the Tōhoku Main Line, but plans to extend the route were suspended after the Tōhoku Main Line was double-tracked. In September 1981, as JNR's financial situation deteriorated, the line was proposed for closure.^[1]

In response, local and prefectural governments along the route established a third-sector railway operator, Abukuma Express, to take over operations. An application for a railway operating license covering the full route between Fukushima and Marumori was submitted on 24 December 1984. The license was granted on 27 February 1985, followed by approval of construction works on 2 March 1985, allowing electrification of the existing section and the resumption of construction on previously unfinished segments.

Ownership of the line was transferred to Abukuma Express on 1 July 1986, with services initially operated as a non-electrified line between Tsukinoki and Marumori using KiHa 22 series [ja] diesel multiple units borrowed from JNR.^[1]

The line was extended south to Fukushima Station on 1 July 1988, completing the full route between Fukushima and Marumori. At the same time, the entire line was electrified using a 20 kV 50 Hz AC overhead supply.

Operations were suspended across the entire line following damage from the 2011 Tōhoku earthquake and tsunami on 11 March 2011, with services gradually restored in stages and full operations resuming on 16 May 2011. All services were again suspended on 12 October 2019 due to damage caused by Typhoon Hagibis; partial service resumed later that month, and full operations between Fukushima and Tsukinoki were restored on 31 October 2020. A further suspension occurred following the 2022 Fukushima earthquake on 16 March 2022, with services progressively reinstated and full operations resuming on 27 June 2022.