Kamiiida Line

The Kamiiida Line has an unusual two-tier structure. The infrastructure is owned by Kami-iida Link Line Co., Ltd. (上飯田連絡線), a third-sector company acting as a Category-3 railway operator, while the Nagoya Municipal Transportation Bureau runs the trains as a Category-2 operator. Kami-iida Link Line also owns the neighbouring Ajiyoshi–Kamiiida section, but that stretch is operated by Meitetsu. When the line opened in 2003 it was driven by Transportation Bureau staff (from the Meijō Line's crew depot), but from April 2007 the Bureau entrusted train operation to Meitetsu, whose Inuyama-based crews now work through between Heian-dōri and Inuyama. Officially, agreements call the line the Nagoya City Rapid Railway Kamiiida Line.

The line's origins lie in a connection that Nagoya lost. The Meitetsu Komaki Line had once reached central Nagoya by rail in two ways — via the Meitetsu Iwakura branch line from Komaki onto the Inuyama Line, or by changing at Kamiiida onto the Onaridōri line of the Nagoya municipal tramway. When the Iwakura branch closed in 1964 and the Onaridōri tram line closed in 1971, the Komaki Line was left without any rail link to the rest of the city, and passengers had to transfer to buses. Restoring that connection became the purpose of the Kamiiida Line.

Plans for a railway through Heian-dōri and Kamiiida go back to a 1972 Urban Transport Council report, which proposed a "Line 7" linking Kanayama, the City Hall area, Heian-dōri and Kamiiida. That scheme lapsed, and in a 1992 Transport Policy Council report (Answer No. 12) the network was redrawn: a route from Ajiyoshi through Kamiiida and Heian-dōri to Shin-sakaemachi and Marutamachi appeared instead, with the Ajiyoshi–Kamiiida–Heian-dōri portion — the Kami-iida Link Line — singled out for urgent construction to improve the connection between the Komaki Line and the Nagoya subway. Kami-iida Link Line Co. was established in 1994, and construction of the Heian-dōri–Kamiiida section was entrusted to the Nagoya Transportation Bureau.

Construction work began on 3 September 1996. The line opened on 27 March 2003, running the single segment between Heian-dōri and Kamiiida, and from the first day it ran through onto the Meitetsu Komaki Line; the Transportation Bureau's new 7000 series trains entered service at the same time. Because the Komaki Line dives beneath the Yada and Shōnai rivers just north of Kamiiida, the line was built deep underground, and both of its stations sit more than twenty metres below the surface. The platforms were laid out long enough for six-car trains in anticipation of future growth, although services run with four-car sets.

A few changes have followed the opening. From 1 April 2007 the Transportation Bureau handed day-to-day train operation to Meitetsu as a rationalisation measure, and on 30 June that year the line received its first timetable revision, improving the connection with the Meijō Line at Heian-dōri. The manaca contactless smart card was introduced on 11 February 2011 and, with other nationwide IC cards, can be used at both stations. A timetable revision on 16 March 2024 cut the number of weekday-morning and weekend-evening trains and removed the printed timetables from the platforms.

Today the Kamiiida Line carries a steady stream of through-passengers between the Komaki Line and central Nagoya via the Meijō Line, but its standalone traffic is modest, since travellers from Kamiiida must change at Heian-dōri. With four trains an hour in the daytime, it has one of the lowest service frequencies of any Japanese subway. The 1992 plan had envisaged extending the line south past the Sakura-dōri and Higashiyama lines toward Marutamachi in Naka Ward, but with the City declaring that it would build no new lines or extensions after the Sakura-dōri Line reached Tokushige, that extension is now considered unlikely.

• 1964The Meitetsu Iwakura branch line closes, removing one of the Komaki Line's rail connections to central Nagoya.
• 1971The Onaridōri line of the Nagoya municipal tramway closes; the Komaki Line is left with no rail link to the rest of the city.
• 1972An Urban Transport Council report (Answer No. 14) proposes a 'Line 7' linking Kanayama, the City Hall area, Heian-dōri and Kamiiida.
• 1992A Transport Policy Council report (Answer No. 12) redraws the plan, flagging the Ajiyoshi–Kamiiida–Heian-dōri Kami-iida Link Line for urgent construction.
• 1994Kami-iida Link Line Co., Ltd. is established; construction of the Heian-dōri–Kamiiida section is entrusted to the Nagoya Transportation Bureau.
• 19963 September: construction work on the line begins.
• 200327 March: the Heian-dōri–Kamiiida section opens; through-service with the Meitetsu Komaki Line begins and the 7000 series enters service.
• 20071 April: the Transportation Bureau entrusts train operation to Meitetsu, whose crews then work through between Heian-dōri and Inuyama.
• 200730 June: the line's first timetable revision since opening improves the connection with the Meijō Line at Heian-dōri.
• 201111 February: the manaca contactless IC card is introduced; both stations accept it and other nationwide IC cards.
• 202416 March: a timetable revision cuts weekday-morning and weekend-evening services and removes the printed timetables from the platforms.