Prewar predecessors

On March 6, 1907, the Tamagawa Electric Railway (玉川電気鉄道, Tamagawa Denki Tetsudō, "Tamaden") opened the first section of an interurban line between Shibuya and what is now Futako-Tamagawa, using 1,372 mm (4 ft 6 in) gauge.^[3] The line was called the Tamagawa Line (玉川線) and is not to be confused with today's Tokyu Tamagawa Line (東急多摩川線). The branch from Sangen-Jaya Station opened on January 18, 1925.

Tama Den-En-Toshi Plan

In 1953, Tokyu Group president Keita Gotō unveiled a "new town" planning scheme called the South-Western Area Development Plan. He envisioned new railway line and freeway and large, clean houses for commuters working in Tokyo.^[4] The railway line would become the Tama Den-En-Toshi Line and the expressway the Tōmei Expressway. The parts of the new line completely overlaps the Tamagawa Line and the project is known as the Shin-Tamagawa Line or "New Tamagawa Line" which runs in an underground alignment under the old interurban line. The Tamagawa Line was closed in 1969 in anticipation for the opening of the Shin-Tamagawa Line, with the remaining branch line of the Tamagawa Electric Railway split off into the present Tokyu Setagaya Line. The underground Shin-Tamagawa Line opened a few years later in 1977, completely replacing the closed interurban line. Upon opening it was treated as a separate line from the Ōimachi Line connecting to said line at Futako-Tamagawa.

Development of the line

In 2000, Tama Den-En-Toshi Line as depicted today was created by merging the Shin-Tamagawa Line and the section of the Ōimachi Line west of Futako-Tamagawa. Trains through servicing into the Tokyo Metro Hanzōmon Line was extended beyond Suitengūmae into Isesaki Line and Nikkō Line of Tobu Railway on March 19, 2003.^[4]

Tokyu has expanded the line to four tracks from Futako-Tamagawa to Mizonokuchi; most trains of the Ōimachi line run through this section to Mizonokuchi, with some local trains making the intermediate stops. This service began in June 2009, postponed from fiscal 2007. Ōimachi line trains, which are 5- or 7-car sets, will then run between Ōimachi and Mizonokuchi.^[5]

Service types

The following three types of service are operated on the line.^[6]

  Local (各駅停車, Kakueki-teisha) (L)

Stops at all stations. Eight services per hour in each direction during the daytime. Two of eight are not through service to the Hanzōmon Line.

  Semi-Express (準急, Junkyū) (SE)

In the morning rush hour, all limited-stop services are semi-express.

In the daytime, two services are operated per hour in each direction and connect to a local train at Shibuya (outbound only), Saginuma and Nagatsuta (inbound only).

  Express (急行, Kyūkō) (Ex)

Not operated in morning rush hour. In the daytime, six services are operated per hour in each direction and two of six is through to the Ōimachi Line. Most express connect to a local train at Sangen-jaya (inbound only), Futako-tamagawa (outbound and through service to the Ōimachi Line), Saginuma and Nagatsuta.

Through trains to Ōimachi Line

On weekends, two seven-car express trains per days are operated to/from Ōimachi and Nagatsuta. Also, a few trains are operated through to/from the Tōkyū Ōimachi Line to utilize forwardings to/from Saginuma depot, up to Ōimachi in the mornings, and down to Saginuma in the late evenings. These formations are 7-car sets, unlike the 10-car trains normally used on the line. A few express trains during the holidays also serve from Chūō-Rinkan in the mornings, down in the evenings.

Footnotes

Current

• Tokyu 2020 series^[7]
• Tokyu 5000 series
• Tokyo Metro 8000 series
• Tokyo Metro 08 series
• Tokyo Metro 18000 series
• Tobu 50000 series
• Tobu 50050 series

• 
  Tokyu 2020 series
• 
  Tokyu 5000 series
• 
  Tokyo Metro 8000 series
• 
  Tokyo Metro 08 series
• 
  Tokyo Metro 18000 series
• 
  Tobu 50050 series

Former

• Tobu 30000 series
• Tokyu 2000 series
• Tokyu 8500 series (1975–2023)^[8]
• Tokyu 8590 series

• 
  Tobu 30000 series
• 
  Tokyu 2000 series
• 
  Tokyu 8500 series
• 
  Tokyu 8590 series