Nagahori Tsurumi-ryokuchi Line

The line takes its name from Nagahori-dōri, a major avenue it follows beneath central Osaka, and from Tsurumi-ryokuchi, a park in the city’s north-east. It was conceived as an access route to that park, which hosted the International Garden and Greenery Exposition (the “Flower Expo,” Expo ’90) in 1990, and also to relieve congestion on the Chūō Line. Because conventional rolling stock would have required a larger and costlier tunnel, the planners adopted an iron-wheel linear-induction motor with the primary mounted on the car — a compact “mini-subway” format never before used in Japan. To gather data and train crews, a test track was built in advance on reclaimed land at Nankō in Osaka’s port district.

The first segment opened on 20 March 1990, running 5.2 km between Kyōbashi and Tsurumi-ryokuchi in time for the Flower Expo; at this stage it was called simply the Tsurumi-ryokuchi Line. As a short, isolated line it touched no other subway, so passengers transferring elsewhere had to change at Kyōbashi via the Osaka Loop Line and similar routes. During the line’s early years two operational milestones followed: all-night running on New Year’s Eve began on 31 December 1994, and one-person (driver-only) operation began on 30 April 1996.

Under the original plan the line would have run along Uemachi-suji to reach the Osaka prefectural government offices near Osaka Castle, but buried cultural artifacts around the castle and the Naniwa Palace site threatened long construction delays, so the route was shifted to Tamatsukuri-suji, which also gave a better interchange with the Chūō Line at Morinomiya. On 11 December 1996 the line was extended 5.7 km from Kyōbashi to Shinsaibashi in downtown Osaka and renamed the Nagahori Tsurumi-ryokuchi Line.

The line reached its full length on 29 August 1997, when it was extended 2.8 km westward from Shinsaibashi to Taishō and 1.3 km eastward from Tsurumi-ryokuchi to Kadoma-minami, completing the 15.0-kilometre route. Through the city centre it functions as an east–west line, but it bends to run north-east–south-west overall, linking the south-western part of Osaka with the north-east and the city of Kadoma. With four interchange stations onto the Osaka Loop Line — Taishō, Tamatsukuri, Morinomiya and Kyōbashi — it has more Loop Line connections than any other Osaka Metro line.

Because it was a late addition to the network, the line generally runs deeper than the older subways it crosses, leaving many of its central platforms well below ground. Platform-edge safety was addressed over fiscal 2010–2011: automatic platform gates entered service at Taishō, the first station so equipped, on 7 July 2010, and were progressively fitted at the remaining stations, with Kadoma-minami completing the rollout on 31 October 2011 so that all 17 stations had them. The station name 大阪ドーム前千代崎 had earlier been shortened to ドーム前千代崎 (Dome-mae Chiyozaki) on 24 December 2006.

On 1 April 2018 the Osaka Municipal Subway was corporatised, and the line passed from the Osaka Municipal Transportation Bureau to the newly formed Osaka Metro Co., Ltd. The line has been worked since its 1990 opening by 70 series linear-motor EMUs in four-car formations; to add capacity, a single four-car 80 series set, transferred and rebuilt from the Imazatosuji Line, entered service on 18 March 2019. Trains are driven automatically (ATO) with a single crew member aboard, run as often as every two to four minutes in the peaks, and are stabled and maintained at the Tsurumi depot.

• 199020 March: the first segment opens — the 5.2 km Kyōbashi–Tsurumi-ryokuchi section, in time for the International Garden and Greenery Exposition; at this stage the line is called the Tsurumi-ryokuchi Line and is Japan’s first iron-wheel linear-motor mini-subway.
• 199431 December: all-night train service begins on New Year’s Eve.
• 199630 April: one-person (driver-only) operation begins.
• 199611 December: the line is extended 5.7 km from Kyōbashi to Shinsaibashi and renamed the Nagahori Tsurumi-ryokuchi Line.
• 199729 August: the line is extended west from Shinsaibashi to Taishō (2.8 km) and east from Tsurumi-ryokuchi to Kadoma-minami (1.3 km), completing the 15.0 km route.
• 200624 December: Ōsaka Dome-mae Chiyozaki Station is renamed Dome-mae Chiyozaki Station.
• 20107 July: automatic platform gates enter service at Taishō, the first station on the line to be so equipped, with progressive installation at other stations following.
• 201131 October: platform gates begin operation at Kadoma-minami, completing installation at all 17 stations.
• 20181 April: the Osaka Municipal Subway is corporatised; the line passes from the Osaka Municipal Transportation Bureau to Osaka Metro Co., Ltd.
• 201918 March: 80 series cars enter service — a single four-car set transferred and rebuilt from the Imazatosuji Line to add capacity.