The Uchibō Line (内房線, Uchibō-sen) is a railway line operated by the East Japan Railway Company (JR East) adjacent to Tokyo Bay, paralleling the western (i.e., inner) shore of the Bōsō Peninsula. It connects Soga Station in the city of Chiba to Awa-Kamogawa Station in the city of Kamogawa, passing through the municipalities of Chiba, Ichihara, Sodegaura, Kisarazu, Kimitsu, Futtsu, Kyonan, Tateyama, and Minamibōsō. The line is connected at both ends to the Sotobō Line. The name of the Uchibō Line in the Japanese language is formed from two kanji characters. The first, 内, means "inner" and the second, 房 is the first character of the Bōsō. The name of the line thus refers to its location along the inner part of the Bōsō Peninsula in relation to the Tokyo Metropolitan Area, as opposed to the Sotobō Line, "outer Bōsō" which is on the opposite side of the peninsula. South of Kimitsu is single track, and north of Kimitsu is double track.
Special Rapid services were discontinued from 4 March 2017.[1]
Commuter Rapid services to/from Keiyo Line were discontinued from 16 March 2024.[2]
Operation
The Uchibō Line operates local service with trains generally originating and terminating at Chiba Station. Trains headed directly for Tokyo Station merge with the Sotobō Line between Soga and Chiba Stations, and with the Sōbu Main Line between Chiba and Tokyo, while express and commuter trains merge with the Keiyō Line from Soga station.
Local trains
A 209 series EMU on a "Local" service in July 2010
Daytime local service from Chiba to Kisarazu and Kimitsu (sometimes to Kazusa-Minato) is provided by around 2 round trips per hour. In addition, 1 round trip per hour runs from Kisarazu to Awa-Kamogawa (and to Kazusa-Ichinomiya through the Sotobō Line).
Keiyō Line through service
Keiyō Line Local, Rapid, and Commuter Rapid trains operate through services on the Uchibō Line between Soga and Kimitsu. In the morning, there are three inbound Rapid and Commuter Rapid trains, and in the evening, there are five outbound Rapid and Commuter Rapid trains and two inbound Local trains. On weekends and holidays, Rapid trains replace the Commuter Rapid trains. One of the inbound morning trains originates from Kazusa-Minato.
Yokosuka Line—Sōbu Line Rapid through service
An E217 series EMU on a "Rapid" service in December 2013
Trains leaving north from Kimitsu connect directly to the Sōbu Line (Rapid), with some continuing onto the Yokosuka Line. Since the October 2004 timetable revision, all trains now stop at Nagaura and Sodegaura stations.
Limited express trains
An E257-500 series EMU on a Sazanami service in October 2006
The limited express train Sazanami runs from Tokyo Station to Kimitsu (and Tateyama station during busy periods). The limited express View Sazanami formerly ran on the Uchibō Line as well, but it was merged with the Sazanami following the timetable revision on December 10, 2005. The limited express Shinjuku Sazanami runs from Shinjuku to Tateyama on weekends and during peak seasons.
The Uchibō line began operation in 1912, and was originally known as the Kisarazu Line (木更津線). It operated from Soga Station to Anegasaki Station in Ichihara. Several extensions were built over the next few years, and in 1919 it reached Awa-Hōjō (present day Tateyama). At this time it was renamed the Hōjō Line (北条線). By 1925 it had been extended to its present-day terminus, Awa-Kamogawa Station.
In 1929, the Hōjō Line was incorporated into the Bōsō Line. However, in 1933, the original section between Soga and Awa-Kamogawa Stations again became its own line, this time renamed the Bōsō West Line (房総西線), and in 1972 it received its current name.
The Soga - Kimitsu section was duplicated between 1964 and 1971, and the entire line was electrified between 1968 and 1971. Individual section dates as given in the Timeline section below.
Timeline
March 28, 1912 – Kisarazu Line (Soga to Anegasaki) begins operation
August 21, 1912 – Extended from Anegasaki to Kisarazu
January 15, 1915 – Extended from Kisarazu to Kazusa-Minato
October 11, 1916 – Extended from Kazusa-Minato to Hamakanaya
August 1, 1917 – Extended from Hamakanaya to Awa-Katsuyama
August 10, 1918 – Extended from Awa-Katsuyama to Nako-Funakata
May 24, 1919 – Extended from Nako-Funakata to Awa-Hōjō; renamed Hōjō Line
June 1, 1921 – Extended from Awa-Hōjō to Minamihara
December 20, 1922 – Extended from Minamihara to Emi
July 25, 1924 – Extended from Emi to Futomi
July 11, 1925 – Extended from Futomi to Awa-Kamogawa
June 16, 1926 – Takeoka station opened
May 20, 1927 – Chitose railyard opened
August 15, 1929 – Bōsō line extended to Awa-Kamogawa; Hōjō Line incorporated into Bōsō Line
August 1, 1930 – Chitose railyard is upgraded to a station
April 1, 1933 – Bōsō line from Soga to Awa-Kamogawa (the run of the former Hōjō Line) is renamed Bōsō West Line
November 20, 1941 – Iwane station opened
March 1, 1946 – Awa-Hōjō station renamed Tateyama Station
January 10, 1947 – Nagaura station opened
April 10, 1956 – Shūsai station renamed Kimitsu Station
July 1, 1964 – Double-track section built between Soga and Hamano
September 20, 1964 – Double track extended from Hamano to Yawatajuku
July 4, 1965 – Double track extended from Yawatajuku to Goi
May 26, 1968 – Double track extended from Goi to Nagaura
July 13, 1968 – Electric wires extended from Chiba station, past Sogo, extending to Kisarazu
March 20, 1969 – Double track extended from Nagaura to Naraba
July 10, 1969 – 135 C57-105 steam engines removed from service
July 11, 1969 – Electric wires extended from Kisarazu to Chikura
March 18, 1970 – Double track extended from Naraba to Kisarazu
March 24, 1970 – Double track extended from Kisarazu to Kimitsu
July 1, 1971 – Electric wires extended from Chikura to Awa-Kamogawa
July 15, 1972 – Renamed Uchibō Line
March 31, 1974 – Naraba station renamed Sodegaura
November 15, 1982 – Freight service between Kisarazu and Awa-Kamogawa discontinued
April 1, 1987 – Acquired by East Japan Railway Company following the division and privatization of JNR initiated by prime minister Yasuhiro Nakasone; Japan Freight Railway Company becomes a second class railway enterprise between Soga and Kisarazu
November 1, 1996 – Japan Freight Railway Company second class enterprise between Soga and Kisarazu is discontinued
February 4, 2001 – ATS-P usage implemented between Chiba and Iwane
March 13, 2021 - E131 series EMUs are introduced on local services between Kisarazu and Awa-Kamogawa, replacing most 209-2000/2100 series trains in that section
References
Wikimedia Commons has media related to Uchibō Line.
^2017年3月ダイヤ改正について [Timetable revision in March 2017] (PDF) (in Japanese). Japan: East Japan Railway Company. Retrieved 18 January 2017.
^"京葉線で通勤快速列車の運転終了" [Commuter Rapid service on Keiyo Line ended]. Japan Railfan Magazine Online (in Japanese). Japan: Koyusha Co., Ltd. 16 March 2024. Retrieved 14 April 2024.
