Utsube Line

The line was conceived and built by the Mie Tramway (三重軌道, Mie Kidō), which laid it as a 762 mm gauge tramway because that gauge was relatively common for such local lines at the time. The first section, from Minami-Hamada (now closed) to Hinaga, opened on 6 October 1912. The tramway was extended toward central Yokkaichi over the next three years: Suwa-mae to Minami-Hamada opened on 16 May 1913, and the segment from Yokkaichi-shi (at the government railway's Kansai Main Line station) to Suwa-mae opened on 25 December 1915, giving the line a city terminus.

In 1916 the operation was reorganised. The Mie Railway (三重鉄道, "Santetsu") was established on 19 July 1916, and on 1 December that year it abolished the Mie Tramway's tramway licence and reopened the Yokkaichi-shi–Hinaga section as a light railway under the Light Railway Act. Steam locomotives worked the line in its early years. The Mie Railway then built a branch southward from Hinaga, intended to reach Suzuka: Hinaga to Ogoso opened on 10 January 1922, and Ogoso to Utsube on 21 June 1922. The planned extension beyond Utsube was never built — surveys had aimed for Ifune, but land acquisition stalled and, after repeated requests to defer the deadline, the railway-construction licence for the extension lapsed in June 1925.

In 1928 the line's northern end was cut back. As the Ise Electric Railway (伊勢電気鉄道) — a predecessor of today's Kintetsu Nagoya Line — extended toward Kuwana, the Yokkaichi-shi–Suwa section was abolished and its trackbed handed to the Ise Electric Railway; the abolition is dated 29 January 1928 in Japanese sources. Gasoline-powered railcars had by then been introduced to replace steam haulage. The whole line was electrified at 600 V DC on 25 December 1943.

Wartime consolidation reshaped the operator. On 11 February 1944 the Mie Railway merged with six other companies to form Mie Transport (三重交通, "Sanco"), and the route was given the name "Utsube Line" on 1 March 1944. For a time the present Hachiōji Line and Yunoyama Line — then also 762 mm gauge — were grouped with it as the "Mie Line," with trains running through between Yunoyama, Kintetsu-Yokkaichi and Utsube.

In 1956, Sanco rerouted the line's Yokkaichi end. Kintetsu was straightening its Nagoya Line, which had many sharp curves around Yokkaichi, and enlarging and relocating Suwa Station about a kilometre westward as Kintetsu-Yokkaichi Station. In step with that work, on 23 September 1956 the section between Suwa and Akahori was abolished and a new line opened between Kintetsu-Yokkaichi (today's Asunarou Yokkaichi) and Akahori, moving the line's terminus. The overhead voltage was later raised from 600 V to 750 V DC in 1959.

The operator changed twice more. On 1 February 1964 Sanco split off its railway business as the Mie Electric Railway (三重電気鉄道, "Sanden"); on 1 March 1964, when the Yunoyama Line was regauged, its through service to the Utsube Line ended. Sanden was short-lived: on 1 April 1965 it was absorbed by the Kinki Nippon Railway (Kintetsu), and the route became the Kintetsu Utsube Line. Under Kintetsu the line was modernised — automatic block signalling and ATS were introduced across the line on 17 March 1989, and one-man (wanman) operation began on 1 June 1989.

In the 2010s the line's future came into question. In 2012 Kintetsu, citing heavy losses on the Utsube and Hachiōji lines, proposed abandoning the rails and converting the route to a dedicated bus road (BRT); Yokkaichi sought instead to keep the railway. In September 2013 Kintetsu and the city agreed to preserve the lines under a public-ownership, private-operation scheme, and the Yokkaichi Asunarou Railway was established on 27 March 2014. From 1 April 2015 the new company took over operations: the city of Yokkaichi owns the track and rolling stock as a Category-3 railway operator, while the Yokkaichi Asunarou Railway runs the trains as a Category-2 operator. On 21 August 2021 ICOCA and other nationwide transport IC cards became usable across the whole line.

• 191128 December: the Mie Tramway (三重軌道) is established to build the line.
• 19126 October: the first section, Minami-Hamada (now closed) to Hinaga, opens as a 762 mm gauge tramway.
• 191316 May: the Suwa-mae–Minami-Hamada section opens.
• 191525 December: the Yokkaichi-shi–Suwa-mae section opens, giving the line a city terminus.
• 191619 July: the Mie Railway (三重鉄道) is established; on 1 December it abolishes the tramway licence and reopens Yokkaichi-shi–Hinaga as a light railway.
• 192210 January: Hinaga–Ogoso opens (Suzuka branch); 21 June: Ogoso–Utsube opens, making Utsube the terminus.
• 1925June: the railway-construction licence for the planned extension beyond Utsube (toward Ifune) lapses after land acquisition stalls.
• 192829 January: the Yokkaichi-shi–Suwa section is abolished and its trackbed transferred to the Ise Electric Railway as it extends toward Kuwana.
• 194325 December: the line is electrified at 600 V DC.
• 194411 February: the Mie Railway and six other firms merge to form Mie Transport (Sanco); 1 March: the route is named the 'Utsube Line'.
• 195623 September: with Kintetsu relocating Suwa Station westward as Kintetsu-Yokkaichi, the Suwa–Akahori section is abolished and a new Kintetsu-Yokkaichi–Akahori line opens, moving the terminus.
• 1959The overhead voltage is raised from 600 V to 750 V DC.
• 19641 February: Sanco splits off its railway as the Mie Electric Railway (Sanden); 1 March: the Yunoyama Line is regauged and its through service to the Utsube Line ends.
• 19651 April: the Mie Electric Railway is absorbed by the Kinki Nippon Railway (Kintetsu); the route becomes the Kintetsu Utsube Line.
• 198917 March: automatic block signalling and ATS are introduced across the whole line; 1 June: one-man (wanman) operation begins.
• 201427 March: the Yokkaichi Asunarou Railway is established after Kintetsu and Yokkaichi agree in 2013 to preserve the line under public ownership and private operation.
• 20151 April: the Yokkaichi Asunarou Railway takes over operations; the city of Yokkaichi owns the track and stock (Category-3 operator) while the railway runs the trains (Category-2 operator).
• 202121 August: ICOCA and other nationwide transport IC cards become usable across the whole line.