Ban'etsu East Line

The line's name pairs the same two characters as the Ban'etsu West Line: 磐 from the old province of Iwaki (Iwashiro) and 越 from Echigo, with "tō" (東) meaning "east." The two Ban'etsu lines meet end-on at Kōriyama but face in opposite directions — the East Line toward the coast at Iwaki, the West Line toward Niigata — and they were never a single through route. The Ban'etsu East Line carries the nickname "Yūyū Abukuma Line" (ゆうゆうあぶくまライン), taken from the Abukuma River that runs near its course, and it follows the gorge of the Natsui River through the highlands for much of its length.

Unlike the West Line, which began as a private undertaking, the Ban'etsu East Line was built by the state from the outset, by the Japanese Government Railways (the Railway Agency). It was conceived as the "Taira Line" (colloquially the Heigun Line) linking Taira — now Iwaki — in the coastal Hamadōri region with Kōriyama in the central Nakadōri region, and was opened from both ends under two names: the Heigun East Line (平郡東線) from the Taira side and the Heigun West Line (平郡西線) from the Kōriyama side.

Construction began on the Kōriyama side. On 21 July 1914 the Heigun West Line opened between Kōriyama and Miharu, a distance of 11.9 km. It was extended on 21 March 1915 from Miharu to Ononiimachi, a further 33.6 km, pushing the railhead east into the hills. The coastal end followed: on 10 July 1915 the Heigun East Line opened between Taira and Ogawagō, 10.3 km. For two years the two lines stopped short of each other in the mountains around the Natsui valley.

The gap was closed on 10 October 1917, when the 29.8 km section between Ogawagō and Ononiimachi opened. With through running established, the Heigun West Line was absorbed into the Heigun East Line and the combined Taira–Kōriyama route was renamed the Ban'etsu East Line, distinguishing it from the Ban'etsu West Line west of Kōriyama. Over the following decades several intermediate stations were added — Iwaki-Tokiwa in 1921, Sugaya in 1948, Kanameta in 1950 among them.

Under Japanese National Railways the line was a rural cross-country route worked by steam. A semi-express named "Iwaki" was introduced on 22 September 1959 and upgraded to an express in 1966. On 1 October 1968 the line was "de-steamed" when the D60 steam locomotives still used on freight and some passenger trains were replaced by DD51 diesel locomotives. The express "Iwaki," which at its peak ran twice a day with a Green car between Mito on the Jōban Line and Fukushima or Sendai, was discontinued on 14 November 1982 as patronage shifted away from the cross-mountain route. On 1 April 1987, with the privatisation of Japanese National Railways, the line passed to JR East, while Japan Freight Railway (JR Freight) took over freight operation on the Ōgoe–Kōriyama section; freight on the Taira–Ōgoe section was abolished the same day.

In the JR era the line became a diesel-railcar local route. From 16 March 1991 all passenger services were taken over by KiHa 110 series diesel railcars based at the Kōriyama depot, with one-man operation introduced on some trains. Taira Station was renamed Iwaki Station on 3 December 1994. Freight traffic dwindled and then ceased entirely: the last freight trains, carrying cement from Ōgoe, ended on 10 March 2000, and JR Freight's operating rights over the Ōgoe–Kōriyama section were formally abolished on 1 April 2001. The opening of the parallel Ban-etsu Expressway in 1995 drew most long-distance passengers onto highway buses, leaving the railway to serve chiefly local commuting and school travel.

The line has been disrupted repeatedly by natural disasters in the twenty-first century. The Great East Japan Earthquake of 11 March 2011 suspended the whole line; service was restored in stages, the Funehiki–Kōriyama section reopening on 31 March, Ononiimachi–Funehiki on 13 April, and the final Iwaki–Ononiimachi section on 15 April 2011. Typhoon Hagibis in October 2019 again cut the line through embankment and bridge washouts; the Ononiimachi–Kōriyama section reopened on 6 November and the whole line on 16 November 2019.

• 191421 July: the state-built Heigun West Line opens between Kōriyama and Miharu (11.9 km).
• 191521 March: the Heigun West Line is extended from Miharu to Ononiimachi (33.6 km).
• 191510 July: the Heigun East Line opens from the coastal end between Taira (the present Iwaki) and Ogawagō (10.3 km).
• 191710 October: the Ogawagō–Ononiimachi section (29.8 km) opens, completing the through route; the Heigun West Line is merged into the Heigun East Line and the combined Taira–Kōriyama line is renamed the Ban'etsu East Line.
• 192110 April: Iwaki-Tokiwa Station opens.
• 195922 September: the semi-express "Iwaki" is introduced (upgraded to an express in 1966).
• 19681 October: the line is de-steamed as the remaining D60 steam locomotives on freight and some passenger trains are replaced by DD51 diesel locomotives.
• 198214 November: the express "Iwaki" (at its peak two round trips daily, with a Green car, running via the line between Mito and Fukushima/Sendai) is discontinued.
• 19871 April: with the privatisation of Japanese National Railways, the line passes to JR East; JR Freight takes over freight on the Ōgoe–Kōriyama section (31.3 km), and freight on the Taira–Ōgoe section is abolished.
• 199116 March: all passenger services are taken over by KiHa 110 series diesel railcars based at the Kōriyama depot, with one-man operation introduced on some trains.
• 19943 December: Taira Station is renamed Iwaki Station.
• 200010 March: the last freight trains, carrying cement from Ōgoe over the Ōgoe–Kōriyama section, are discontinued, ending all freight on the line.
• 20011 April: JR Freight's second-class operating rights over the Ōgoe–Kōriyama section are formally abolished.
• 201111 March: the Great East Japan Earthquake suspends the whole line; service is restored in stages — Funehiki–Kōriyama on 31 March, Ononiimachi–Funehiki on 13 April, and Iwaki–Ononiimachi on 15 April, completing full restoration.
• 2019October–November: Typhoon Hagibis washes out embankments and a bridge, cutting the line; the Ononiimachi–Kōriyama section reopens on 6 November and the whole line on 16 November.