The is a railway line in Japan operated by the

East Japan Railway Company The is a major passenger railway company in Japan and the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as in Japanese. The company's headquarters are in ...

(JR East) adjacent to the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

, on the eastern (i.e., outer) side of the

Bōsō Peninsula The is a peninsula that encompasses the entirety of Chiba Prefecture on Honshu, the largest island of Japan. It is part of the Greater Tokyo Area. It forms the eastern edge of Tokyo Bay, separating it from the Pacific Ocean. The peninsula covers ...

. It connects

Chiba Station is a major interchange railway station in Chiba, Chiba, Japan, operated by East Japan Railway Company (JR East) and Chiba Urban Monorail. Lines Chiba Station is served by the following lines. JR East *Sobu Main Line ** Chūō-Sōbu Line ** S ...

in Chiba to

Awa-Kamogawa Station is a junction passenger railway station in the city of Kamogawa, Chiba Prefecture Japan, operated by the East Japan Railway Company (JR East). Lines Awa-Kamogawa Station is served by the Sotobō Line and Uchibō Line, and forms the terminatin ...

in Kamogawa, passing through Ōamishirasato, Mobara, Chōsei,

Ichinomiya is a Japanese language, Japanese historical term referring to the Shinto shrines with the highest rank in a Provinces of Japan, province. Shrines of lower rank were designated , , , and so forth.''Encyclopedia of Shinto'' ''Ichi no miya'' retr ...

, Isumi, Onjuku, and Katsuura. The line is connected to the Uchibō Line at both ends. South of Kazusa-Ichinomiya is single track, and north of Kazusa-Ichinomiya is double track.

Services

In addition to local services,

limited express A limited express is a type of express train or express bus service that stops at fewer locations compared to other express services on the same or similar routes. Japan The term "limited express" is a common translation of the Japanese ...

and Rapid services run on this line. *Limited Express '' Wakashio'' : – (

Keiyō Line The is a railway line connecting Tokyo and Chiba in Japan, paralleling the edge of Tokyo Bay. It is operated by the East Japan Railway Company (JR East). The line forms part of what JR East refers to as the around Tokyo, consisting of the Ke ...

) – – :(some operate as all-stations "Local" services between and Awa-Kamogawa *Rapid ** – (

Yokosuka Line The is a railway line in Japan operated by the East Japan Railway Company (JR East). The Yokosuka Line connects Tokyo Station with in Yokosuka, Kanagawa. Officially, the name Yokosuka Line is assigned to the segment between and Kurihama sta ...

) – Tokyo – (

Sōbu Line (Rapid) The Sōbu Line (Rapid) () is a railway service on the Sōbu Main Line in Tokyo and Chiba Prefecture, Japan, operated by East Japan Railway Company (JR East). It connects Tokyo Station in Chūō, Tokyo with Chiba Station in Chūō-ku, Chiba via ...

) – Soga – **Tokyo – (Keiyō Line) – Soga – – Kazusa-Ichinomiya (some to/from Katsuura, or on the

Tōgane Line The is a railway line in Chiba Prefecture, Japan, owned and operated by East Japan Railway Company (JR East). It connects Ōami Station in the city of Ōamishirasato, Chiba, Ōamishirasato and Narutō Station in the city of Sanmu, Chiba, Sanmu. ...

) ***Commuter Rapid services through to/from the Keiyō Line also used to operate, but they have been discontinued as of 16 March 2024.

Station list

; Legend * ● : All trains stop * (●) : Some trains stop * , : All trains pass ; Notes * Local trains stop at every station.

Rolling stock

Local service * E131 series 2-car EMUs (since 13 March 2021) * 209-2000/2100 series 4/6-car EMUs Keiyō Line through service Between and : *

209-500 series Working time or laboring time is the period of time that a person spends at paid Wage labour, labor. Unpaid work, Unpaid labor such as personal housework or caring for children or pets is not considered part of the working week. Many countri ...

10-car EMUs * E233-5000 series 6+4-car and 10-car EMUs Sōbu Line (Rapid) through service Between and : * E235-1000 series 11+4-car EMUs (since 21 December 2020) ''Wakashio'' ''and'' ''Shinjuku Wakashio'' Limited Express * E257-500 series 5-car EMUs

Former rolling stock

* 113 series EMUs (Sotobō Line local services, until 2011) * 211-3000 series 5-car EMUs (Sotobō Line local services from 21 October 2006 to spring 2013) *

E217 series The was a suburban electric multiple unit (EMU) train type operated by East Japan Railway Company (JR East) in the Kantō region of Japan from 1994 to 2025. Design Introduced in 1994 to replace the 113 series EMUs running on the Sōbu Line (R ...

11+4-car EMUs (until 15 March 2025)

History

Railway that connects Chonan with Mobara

The Boso Railway opened the Chiba to Oami section in 1896, extending the line to Kazusa-Ichinomiya the following year and to Ohara in 1899. The company was nationalised in 1907. The extension to Katsuura opened in 1913, to Kazusa-Okitsu in 1927, and Awa-Kamogawa in 1929. A new tunnel and associated deviation was opened at Toke in 1954 to improve the

loading gauge A loading gauge is a diagram or physical structure that defines the maximum height and width dimensions in railway vehicles and their loads. Their purpose is to ensure that rail vehicles can pass safely through tunnels and under bridges, and k ...

of the line. The Chiba to Soga section was double-tracked between 1960 and 1963, extended to Nagata between 1972 and 1974, with CTC signalling being commissioned between Soga and Awa-Kamogawa in 1974. The line to Kazusa-Ichinomiya was double-tracked between 1980 and 1986, with the Onjuku to Katsuura section double-tracked in 1995, and the Torami to Chojamachi section the following year. The entire line was electrified in 1968, and freight services ceased between 1982 and 1987.

Former connecting lines

* Mobara Station: The Mobara Town Council operated a , gauge

handcar A handcar (also known as a pump trolley, pump car, rail push trolley, push-trolley, jigger, Kalamazoo, velocipede, gandy dancer cart, platelayers' cart, draisine, or railbike) is a railroad car powered by its passengers or by people pushing t ...

line to Tai Muko between 1909 and 1924. The council then decided to build a railway to connect to the Kominato Line. of gauge line was opened as far as Okuno between 1930 and 1933, the first following the handcar line alignment. Poor patronage and economic circumstances led to the line being closed in 1939. * Ohara Station: The Chiba Prefectural Government opened a , gauge

line to Otaki in 1912. A railcar was converted to petrol engine power in 1922. The line closed in 1927 to allow for the construction of the Isumi Line, which opened on the same alignment in 1930.

Accidents

On 8 May 2020, at 3:55 pm, the front carriage of a local service derailed between Awa-Kamogawa and Awa-Amatsu stations. Around 20 passengers and crew were on board the train (a 209 Series) when it derailed. One person was taken to a hospital.

References

External links

JR East Sōbu and Bōsō area route map
{{DEFAULTSORT:Sotobo Line Lines of East Japan Railway Company Railway lines in Chiba Prefecture 1067 mm gauge railways in Japan Railway lines opened in 1896