Sakurajima Line

The line began not as an independent route but as part of the Nishinari Line, built by the private Nishinari Railway. On 5 April 1898 the company opened its line from Osaka Station to Ajikawaguchi — about 5.87 km — with freight-only operation between Osaka and Fukushima and new stations at Fukushima, Noda and Ajikawaguchi; Nishikujō Station followed on 1 October that year. Passenger services between Osaka and Fukushima began on 1 May 1899. In December 1904 the line was leased to the government's Railway Operation Bureau, and on 1 April 1905 it was extended from Ajikawaguchi to Tenpōzan (about 1.61 km), a new harbour-side terminus.

The Nishinari Railway was nationalised on 1 December 1906. When the government's railway-line naming scheme was issued on 12 October 1909, the Osaka–Tenpōzan route was formally designated the Nishinari Line. On 15 April 1910 the short Ajikawaguchi–Tenpōzan section was abolished and replaced by a new Ajikawaguchi–Sakurajima segment: Tenpōzan Station closed and Sakurajima Station opened, the change amounting in practice to an extension and the relocation and renaming of the former terminus. The Fukushima–Nishikujō–Ajikawaguchi stretch was double-tracked in July 1912.

Gasoline railcar services began on 25 March 1934, using KiHa 42000 cars. On 29 January 1940 a gasoline railcar derailed and caught fire in Ajikawaguchi Station — the Nishinari Line derailment-and-fire accident — killing 189 people and injuring 69, one of the deadliest rail accidents in pre-war Japan. The Osaka–Sakurajima section was electrified at 1,500 V DC on 1 May 1941, and on 21 November 1943 a freight branch was opened from Ajikawaguchi to Ōsaka-Hokkō.

The modern Sakurajima Line was created on 25 April 1961. When the Osaka Loop Line was completed, the Nishikujō–Sakurajima section (then 4.5 km) was split off — together with the Ajikawaguchi–Ōsaka-Hokkō freight branch — and renamed the Sakurajima Line. Sakurajima Station was relocated about 0.5 km in March 1966, and through running with the Osaka Loop Line was discontinued on 25 March 1968. The Ajikawaguchi–Ōsaka-Hokkō freight branch was abolished on 15 November 1982, freight on the Ajikawaguchi–Sakurajima section ended in November 1986, and on 1 April 1987, with the privatisation of Japanese National Railways, the line passed to JR West, while JR Freight became the second-type operator over the Nishikujō–Ajikawaguchi section.

The line was transformed by Universal Studios Japan. To clear the site for the theme park, on 1 April 1999 the Ajikawaguchi–Sakurajima section was switched onto a newly built double-track alignment and Sakurajima Station was relocated again; an old lift-bridge over the Hokkō Canal, disused since the waterway was filled in, was left behind. Universal City Station, the park's nearest station, opened on 1 March 2001, and at the same time JR West adopted the 'JR Yumesaki Line' nickname — chosen in a public poll for its pleasant sound and the idea that the bayside area around the line was where 'Osaka's dreams' were coming into bloom. Through operation with the Osaka Loop Line, suspended during the works, resumed on 3 March 2001.

To move large crowds reliably to and from the park, the Nishikujō–Universal City section was rebuilt as twin single track in December 2002, allowing trains to run in either direction on either track if one line is blocked. Newer rolling stock followed: 201 series trains entered service in 2005, and from 25 December 2016 the line's regular trains were replaced by 323 series eight-car sets, with the older 103 series bowing out in 2017 and the 201 series in 2019. Station numbers were introduced across the line on 17 March 2018. During the 2025 World Exposition in Osaka, JR West ran a temporary 'Expo Liner' rapid service between Shin-Ōsaka and Sakurajima via the Umeda freight line and the Sakurajima Line from 15 March to 13 October 2025.

• 18985 April: the private Nishinari Railway opens its line from Osaka Station to Ajikawaguchi (about 5.87 km); Osaka-Fukushima is freight-only and Fukushima, Noda and Ajikawaguchi stations open. Nishikujo Station opens on 1 October.
• 18991 May: passenger services begin between Osaka and Fukushima.
• 19041 December: the line is leased to the government's Railway Operation Bureau.
• 19051 April: the line is extended from Ajikawaguchi to Tenpozan (about 1.61 km); Tenpozan Station opens.
• 19061 December: the Nishinari Railway is nationalised.
• 190912 October: under the national railway-line naming scheme, the Osaka-Tenpozan route is formally named the Nishinari Line.
• 191015 April: the Ajikawaguchi-Tenpozan section is abolished and Ajikawaguchi-Sakurajima opens; Tenpozan Station closes and Sakurajima Station opens (in effect an extension and relocation/renaming of the terminus).
• 193425 March: gasoline railcar (KiHa 42000) services begin.
• 194029 January: a gasoline railcar derails and catches fire at Ajikawaguchi Station (the Nishinari Line derailment-and-fire accident), killing 189 and injuring 69.
• 19411 May: the Osaka-Sakurajima section is electrified at 1,500 V DC.
• 194321 November: a freight branch opens from Ajikawaguchi to Osaka-Hokko (3.4 km).
• 196125 April: on completion of the Osaka Loop Line, the Nishikujo-Sakurajima section (then 4.5 km) and the Ajikawaguchi-Osaka-Hokko freight branch are split off and renamed the Sakurajima Line.
• 196825 March: through running with the Osaka Loop Line is discontinued (Sakurajima Station had been relocated about 0.5 km in March 1966).
• 198215 November: the Ajikawaguchi-Osaka-Hokko freight branch is abolished and Osaka-Hokko Station closes.
• 19871 April: with the privatisation of Japanese National Railways, the line passes to JR West; JR Freight becomes the second-type operator over Nishikujo-Ajikawaguchi.
• 19991 April: to avoid the planned USJ site, the Ajikawaguchi-Sakurajima section is switched to a new double-track alignment and Sakurajima Station is relocated again (+0.1 km).
• 20011 March: Universal City Station opens and JR West adopts the 'JR Yumesaki Line' nickname; through running with the Osaka Loop Line resumes on 3 March.
• 20026 December: the Nishikujo-Universal City section is converted to twin single track, allowing single-line operation on either track.
• 201625 December: 323 series eight-car trains enter service on the line, replacing older stock (103 series withdrawn 2017, 201 series 2019).
• 201817 March: station numbers are introduced across the line.
• 202515 March - 13 October: a temporary 'Expo Liner' rapid service runs between Shin-Osaka and Sakurajima for the Osaka-Kansai Expo, via the Umeda freight line and the Sakurajima Line.