|Tokyo Metro Namboku Line|
|Rolling stock||Tokyo Metro 9000 series, Saitama Rapid Railway 2000 series, Tokyu 3000 series, Tokyu 5080 series|
|Daily ridership||522,736 (2017)|
|Opened||November 29, 1991|
|Line length||21.9 km (13.6 mi)|
|Track gauge||1,067 mm (3 ft 6 in)|
|Electrification||1,500 V DC overhead catenary|
|Operating speed||80 km/h (50 mph)|
The Tokyo Metro Namboku Line (東京メトロ南北線, Tōkyō Metoro Namboku-sen, South-North Line) is a subway line owned and operated by Tokyo Metro in Tokyo, Japan. The line runs between Meguro in Shinagawa and Akabane-Iwabuchi in Kita. The Namboku Line was referred to as Line 7 during the planning stages, thus the seldom-used official name is Line 7 Namboku Line (7号線南北線, Nana-gō-sen Namboku-sen).
On maps, diagrams and signboards, the line is shown using the color emerald(previously coded "teal"), and its stations are given numbers using the letter "N".
Trains run through onto the Tokyu Meguro Line for Hiyoshi and the Saitama Railway's Saitama Rapid Railway Line (which is essentially a separately-owned extension of the Namboku Line) for Urawa-Misono.
The right-of-way and stations between Shirokane-Takanawa and Meguro are shared with the Toei Mita Line – a unique situation on the Tokyo subway where both operators share common infrastructure. Under an agreement between Tokyo Metro and the Tokyo Metropolitan Government, the fare for this section is calculated on the Toei fare system for passengers traveling to stations on the Mita Line past Shirokane-Takanawa, on the Metro fare system for passengers traveling to stations on the Namboku Line past Shirokane-Takanawa, and on the system "most beneficial to the passenger" (presently the Metro schedule) for travel solely on the shared sector.
On maps, diagrams and signboards, the Namboku Line is shown using the color emerald (▉), and its stations are given numbers using the letter "N".
|↑ Through-running to/from Hiyoshi via Tokyu Meguro Line ↑|
|Shirokanedai||白金台[* 2]||1.3||1.3||Toei Mita Line (I-02) (shared)||Minato|
|Shirokane-takanawa||白金高輪[* 2]||1.0||2.3||Toei Mita Line (I-03) (shared)|
|Azabu-juban||麻布十番||1.3||3.6||Toei Oedo Line (E-22)|
|Akabane-iwabuchi||赤羽岩淵[* 3]||1.1||21.3||Saitama Rapid Railway Line|
|↓ Through-running to/from Urawa-Misono via the ■ Saitama Rapid Railway Line ↓|
The 21.3 km Namboku Line is one of Tokyo Metro's newer lines, featuring advanced technology including full automatic train operation and platform screen doors. Although the line was originally proposed in 1968, construction did not begin until the 1980s, partly due to the right-of-way to Meguro with the Toei Mita Line. The first segment from Komagome to Akabane-Iwabuchi opened on November 29, 1991.
The line initially operated with four-car EMUs. Upon its extension to Yotsuya in March 1996, the formations were extended to six cars. All stations have enough clearance for extending to eight-car trains, but trains of this length have not started running. The Namboku line will possibly start operating 8 car trains in fiscal year 2022.
The extension to Tameike-Sannō was completed in September 1997, and the last stretch from Tameike-Sanno to Meguro was completed on September 26, 2000, when through service to the Tokyu Meguro Line started. Through service with the Saitama Rapid Railway Line commenced when it opened in March 2001 and accommodated traffic to and from Saitama Stadium during the 2002 World Cup. Although the Saitama Line is more or less a northern extension of the Namboku Line, it nevertheless remains a private entity to which the Namboku Line offers through services with.
On 28 January 2022, Tokyo Metro announced that a 2.5 km (1.6 mi) spur line from Shirokane-takanawa to Shinagawa would be built. The extension is expected to cost ¥131 billion (2021) (US$1.23 billion) and scheduled to begin revenue service in the mid-2030s. It is intended to increase connections to and from the Chūō Shinkansen, which is scheduled to open for service in 2027.