Ōimachi Line
A 6020 series EMU on an Ōimachi Line local service in October 2025
Overview
Native name	大井町線
Status	In service
Owner	Tokyu Corporation
Line number	OM
Locale	Tokyo and Kanagawa Prefecture
Termini	Mizonokuchi Ōimachi
Stations	16
Color on map	Orange (#f18c43)
Service
Type	Commuter rail
System	Tokyu Railways
Operator	Tokyu Corporation
Daily ridership	511,214 (FY2018)[1]
History
Opened	6 July 1927 (6 July 1927)
Technical
Line length	12.4 km (7.7 mi)
Track gauge	1,067 mm (3 ft 6 in)
Electrification	1,500 V DC overhead catenary
Operating speed	95 km/h (59 mph)
Route map km 0.0 Ōimachi Tokyo Waterfront Area Rapid Transit 0.8 Shimo-Shimmei Yokosuka Line Tōkaidō Shinkansen 1.5 Togoshi-kōen Toei Asakusa Line 2.1 Nakanobu 2.7 Ebaramachi Tōkyū Ikegami Line 3.2 Hatanodai 4.0 Kita-Senzoku Tōkyū Meguro Line 4.8 Ōokayama Okusawa depot 5.3 Midorigaoka 6.3 Jiyūgaoka Tōkyū Tōyoko Line Jiyūgaoka depot 7.1 Kuhombutsu 7.8 Oyamadai 8.3 Todoroki 9.2 Kami-noge Tōkyū Den-en-toshi Line 10.4 Futako-Tamagawa Tama River Tokyo Kanagawa border 11.1 Futako-Shinchi 11.7 Takatsu 12.4 Mizonokuchi Musashi- Mizonokuchi Nambu line Kajigaya Kajigaya depot Saginuma depot Saginuma Nagatsuta Nagatsuta depot Chūō-Rinkan

The Ōimachi Line (大井町線, Ōimachi-sen) is a railway line in Japan operated by the private railway operator Tokyu Corporation. It extends from Ōimachi in Shinagawa, Tokyo to Mizonokuchi in Kawasaki, Kanagawa.

All-stations "Local" services are classified as blue and green. The latter runs on the express track between Futako-Tamagawa and Mizonokuchi and does not stop at Futako-Shinchi or Takatsu. Limited-stop "Express" services are also provided.

On weekends, two seven-car express trains per days are operated to/from Ōimachi and Nagatsuta on the Tokyu Den-en-toshi Line. Also, a few trains are operated through down to Saginuma in the late evenings. A few express trains during the holidays also serve from Chūō-Rinkan in the mornings, down in the evenings.

No.	Station	Japanese	Distance (km)	Stops			Transfers	Location
				"Blue"Local	"Green"Local	Express
	Ōimachi	大井町	0.0	●	●	●	Keihin–Tōhoku Line (JK19) Rinkai Line (R-07)	Shinagawa	Tokyo
	Shimo-shimmei	下神明	0.8	●	●	|
	Togoshi-kōen	戸越公園	1.5	●	●	|
	Nakanobu	中延	2.1	●	●	|	Asakusa Line (A-03)
	Ebaramachi	荏原町	2.7	●	●	|
	Hatanodai	旗の台	3.2	●	●	●	Ikegami Line (IK05)
	Kita-senzoku	北千束	4.0	●	●	|		Ōta
	Ōokayama	大岡山	4.8	●	●	●	Meguro Line (MG06)	Meguro
	Midorigaoka	緑が丘	5.3	●	●	|
	Jiyūgaoka	自由が丘	6.3	●	●	●	Tōyoko Line (TY07)
	Kuhombutsu	九品仏	7.1	●	●	|		Setagaya
	Oyamadai	尾山台	7.8	●	●	|
	Todoroki	等々力	8.3	●	●	|
	Kaminoge	上野毛	9.2	●	●	|
	Futako-tamagawa	二子玉川	10.4	●	●	●	Den-en-toshi Line (DT07)
	Futako-shinchi	二子新地	11.1	●	|	|	Den-en-toshi Line (DT08)	Takatsu-ku, Kawasaki	Kanagawa
	Takatsu	高津	11.7	●	|	|	Den-en-toshi Line (DT09)
	Mizonokuchi	溝の口	12.4	●	●	●	Den-en-toshi Line (DT10; Limited through service) Nambu Line (Musashi-Mizonokuchi: JN10)
↓ Limited through services into the Den-en-toshi Line. "Blue" local trains to/from Saginuma; Express trains to/from Nagatsuta and Chūō-rinkan ↓

^[2]

• 6020 series five-car EMUs (from July 2025)^[3]
• 9000 series five-car EMUs
• 9020 series five-car EMUs^[4]

• 
  A 9000 series EMU in December 2021
• 
  A 9020 series EMU in December 2021
• 
  A 5-car 6020 series EMU in August 2025

• 6000 series seven-car EMUs (since March 2008, originally delivered as six-car sets)
• 6020 series seven-car EMUs (from March 2018)

• 
  A 6000 series EMU in March 2018
• 
  A 6020 series EMU in December 2018

• 8000 series
• 8090 series
• 8590 series
• 8500 series

• 6 July 1927: The section between Ōimachi and Ōokayama was opened by the Meguro-Kamata Electric Railway (目黒蒲田電鉄).
• 1 November 1929: The section between Jiyūgaoka and Futako-tamagawa was opened by the Meguro-Kamata Electric Railway.
• 25 December 1929: The section between Ōokayama and Jiyūgaoka was opened by Meguro-Kamata Electric Railway.
• 29 June 1938: The Meguro-Kamata Railway was absorbed into the Tokyo-Yokohama Electric Railway (東京横浜電鉄).
• 15 January 1958: Electric supply was raised to 1,500 V DC.
• 11 October 1963: The line was renamed the Den-en-toshi Line, together with the section south of Futako-tamagawa.
• 16 November 1977: Through running started between Shibuya and Nagatsuta.
• 12 August 1979: The line was renamed the Ōimachi Line and separated from the Den-en-toshi Line south of Futako-tamagawa.
• 23 February 2008: ATS was replaced by ATC.
• 28 March 2008: Express services started.
• 11 July 2009: The Ōimachi Line was extended to Mizonokuchi from Futako-tamagawa.

Express services on the line were lengthened from six to seven cars in late fiscal 2017, and the platforms at Ōimachi, Hatanodai, and Jiyūgaoka were lengthened to handle the longer trains.^[5] Since December 2018, "Q Seat" reserved seating has been implemented on some express services that run between Ōimachi and Nagatsuta stations.^[6]

• Tokyu Corporation website (in English)

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