Editing Den-en-toshi Line (section)

===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 {{STN|Futako-Tamagawa|x}}.{{citation needed|date=March 2020}} Trains through servicing into the [[Tokyo Metro Hanzōmon Line]] was extended beyond {{STN|Suitengūmae|x}} into [[Tōbu Isesaki Line|Isesaki Line]] and [[Tōbu Nikkō Line|Nikkō Line]] of [[Tobu Railway]] on March 19, 2003.<ref name="TokyuHistory"/>

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 {{STN|Ōimachi|x}} and Mizonokuchi.<ref>{{Cite web |title=3月28日 大井町線の急行運転を開始。田園都市線の混雑緩和をめざします。 |trans-title=March 28 Express service on the Oimachi Line begins. We aim to alleviate congestion on the Den-en-toshi Line. |url=http://www.tokyu.co.jp/railway/oimachi-kyuko/outline/index.html |url-status=dead |archive-url=https://web.archive.org/web/20090303053401/http://www.tokyu.co.jp/railway/oimachi-kyuko/outline/index.html |archive-date=3 March 2009 |access-date=6 August 2022 |website=tokyu.co.jp}}</ref>