Akabane Line

…The Ikebukuro-Tabata section opened in April 1903, and was purchased by the government in November 1906. When the line was named in 1909, the Akabane-Shinagawa and Ikebukuro-Tabata sections were designated the Yamanote Line. In July 1972, the 5.5 km section between Ikebukuro and Akabane was separated into the Akabane Line, taking into consideration the train operation. After nationalization, the line developed remarkably as an urban line with the concentration of population in Tokyo, and construction of a dedicated line between Tabata and Ueno was also carried out, and in December 1909, train service began between Karasumori (now Shimbashi) - Shinagawa - Ikebukuro - Ueno. …

*Some of the terms mentioned in relation to the Akabane Line are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…1903年4月池袋～田端間が開業し，06年11月国に買収され，09年の線路名称制定とともに赤羽～品川間および池袋～田端間が山手線と定められた。72年7月池袋～赤羽間5.5kmは電車の運行形態等を勘案し赤羽線として独立した。国有化以後同線は東京への人口集中とともに市街地線としてめざましく発展し，田端～上野間等の専用線工事も進められ，1909年12月には烏森(現，新橋)～品川～池袋～上野間に電車運転も開始された。…

※「赤羽線」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報