Yamanote Line - History

History

The Yamanote Line originated in 1885 with the construction of the Shinagawa Line (品川線, -sen?) between Shinagawa and Akabane, bypassing the then built up areas and providing the first north-south rail link through Tokyo. The top part of the loop between Ikebukuro and Tabata was completed in 1903 (known as the Toshima Line (豊島線, -sen?)) and following electrification in 1909 both lines were merged to become the Yamanote Line. The loop was not complete at this time, so trains generally inter-operated with the Chūō and Keihin-Tōhoku lines, traveling from Nakano to Tokyo Station, south to Shinagawa, then clockwise around the Yamanote Line to Tabata.

The loop was completed in 1925 with the opening of the section of track between Kanda and Ueno, providing a north-south link via Tokyo Station through the city's business centre. A parallel freight line, also completed in 1925, ran along the inner side of the loop between Shinagawa and Tabata.

During the prewar era, the Ministry of Railways did not issue permits to private suburban railway companies for new lines to cross the Yamanote from their terminal stations to the central districts of Tokyo, forcing to terminate services at stations on the line. This policy led to the development of new urban centers (新都心、副都心, shintoshin, fukutoshin?) around major transfer points on the Yamanote Line, most notably at Shinjuku and Ikebukuro (which are now the two busiest passenger railway stations in the world).

The contemporary Yamanote Line came into being in 1956 when it was separated from the Keihin-Tōhoku Line and given its own set of tracks along the eastern side of the loop between Shinagawa and Tabata. However, Yamanote Line trains continued to periodically use the Keihin-Tōhoku tracks, particularly on holidays and during off-peak hours, until rapid service trains were introduced on the Keihin-Tōhoku Line in 1988.

A major explosion on the Yamanote Freight Line in Shinjuku in 1967 led to the diversion of freight traffic to the more distant Musashino Line. To address severe undercapacity, the freight line was repurposed for use by Saikyō Line and Shōnan-Shinjuku Line trains, as well as certain limited express trains such as the Narita Express and some liner services. Likewise, there are currently plans to extend the Tōhoku Main Line to Tokyo Station to provide further relief on the busiest portion of the Yamanote Line today, the southbound segment between Ueno and Okachimachi.