Sotobō Line

Railway line in Chiba prefecture, Japan

  • Chiba
  • Awa-Kamogawa
Stations27ServiceTypeHeavy railOperator(s)JR EastDepot(s)ChibaHistoryOpened1896TechnicalLine length93.3 km (58.0 mi)Track gauge1,067 mm (3 ft 6 in)Operating speed110 km/h (70 mph)
Route map
Sotobo Line
Legend
1
2
3
 1: Keisei Chiba Line
2: Chūō-Sōbu Line
3: Sōbu Line (Rapid)
0.0
 Chiba
(II) 1963–
Chiba Monorail Line 1
Keisei Chiba Station (II) 1958–
Chiba Station
(I) -1963
Keisei Chiba Station (I) -1958
Chiba Monorail Line 2
 Hon-Chiba Station
(I) -1958
1.4
 Hon-Chiba
(II) 1958–
Keisei Chihara Line
3.8
 Soga
8.8
 Kamatori
12.6
 Honda
18.1
 Toke
Toke Tunnel
881m
22.9
 Ōami
(II)
 Ōami Station
(I)
25.3
 Nagata
27.7
 Honnō
31.4
 Shin-Mobara
JASDF Mobara Airfield
Nansō Line (defunct)
Kazusa-Takashi Station
34.3
 Mobara
Chōnan-Mobara Jinrikisha Rail Line
38.9
 Yatsumi
Ichinomiya River
43.0
 Kazusa-Ichinomiya
46.2
 Torami
49.3
 Taitō
Izumi River
52.1
 Chōjamachi
53.7
 Mikado
55.6
 Tōkai Station
(closed)
57.2
 Ōhara
Isumi Kidō Jinrikisha Line
60.5
 Namihana
65.4
 Onjuku
70.9
 Katsuura
Ubara Tunnel
74.3
 Ubara
Okitsu Tunnel
77.2
 Kazusa-Okitsu
80.5
 Namegawa-Island
Uchiura Tunnel
84.3
 Awa-Kominato
Ōboiso Tunnel
87.7
 Awa-Amatsu
93.3
 Awa-Kamogawa

The Sotobō Line (外房線, Sotobō-sen) is a railway line in Japan operated by the East Japan Railway Company (JR East) adjacent to the Pacific Ocean, on the eastern (i.e., outer) side of the Bōsō Peninsula. It connects Chiba Station in Chiba to Awa-Kamogawa Station in Kamogawa, passing through Ōamishirasato, Mobara, Chōsei, Ichinomiya, 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 and Rapid services run on this line.

Tokyo – (Keiyō Line) – Soga – Awa-Kamogawa
(some operate as all-stations "Local" services between Katsuura and Awa-Kamogawa
  • Rapid
    • Kurihama – (Yokosuka Line) – Tokyo – (Sōbu Line (Rapid)) – Soga – Kazusa-Ichinomiya
    • Tokyo – (Keiyō Line) – Soga – Ōami – Kazusa-Ichinomiya (some to/from Katsuura, or Narutō on the Tōgane Line)
      • Commuter Rapid services through to/from the Keiyō Line also used to operate, but they have been discontinued as of 16 March 2024.[1]

Station list

Legend
  • ● : All trains stop
  • (●) : Some trains stop
  • | : All trains pass
Notes
  • Local trains stop at every station.
Station Japanese Distance (km) to/from

Keiyō Line

to/from

Sōbu Line (Rapid) and Yokosuka Line

Transfers Location
(in Chiba)
Keiyō Line Rapid Limited express
Wakashio 		Sōbu Line Rapid Limited express
Shinjuku Wakashio

(Weekends only)

Chiba 千葉 0.0 ● ● JO Sōbu Line (Rapid) (JO28) (some through services)

JB Chūō-Sōbu Line (JB39)

■ Sōbu Main Line

■ Narita Line

Chiba Urban Monorail Line 1, Line 2

KS Keisei Chiba Line (Keisei Chiba: KS59)

Chūō-ku, Chiba
Hon-Chiba 本千葉 1.4 ● |  
Soga 蘇我 3.8 ● ● ● ● JE Keiyō Line (some through services)

■ Uchibō Line

Kamatori 鎌取 8.8 ● | ● |   Midori-ku, Chiba
Honda 誉田 12.6 ● | ● |  
Toke 土気 18.1 ● (●) ● |  
Ōami 大網 22.9 ● ● ● ● ■ Togane Line Ōamishirasato
Nagata 永田 25.3 (●) | | |  
Honnō 本納 27.7 (●) | | |   Mobara
Shin-Mobara 新茂原 31.4 (●) | | |  
Mobara 茂原 34.3 ● ● ● ●  
Yatsumi 八積 38.9 (●) | | |   Chōsei
Kazusa-Ichinomiya 上総一ノ宮 43.0 ● ● ● ●   Ichinomiya
Torami 東浪見 46.2 ● | |  
Taitō 太東 49.3 ● | |   Isumi
Chōjamachi 長者町 52.1 ● | |  
Mikado 三門 53.7 ● | |  
Ōhara 大原 57.2 ● ● ● ■ Isumi Line
Namihana 浪花 60.5 ● | |  
Onjuku 御宿 65.4 ● ● ●   Onjuku
Katsuura 勝浦 70.9 ● ● ●   Katsuura
Ubara 鵜原 74.5   | |  
Kazusa-Okitsu 上総興津 77.2 (●) ●  
Namegawa-Island 行川アイランド 80.5 | |  
Awa-Kominato 安房小湊 84.3 ● ●   Kamogawa
Awa-Amatsu 安房天津 87.7 | |  
Awa-Kamogawa 安房鴨川 93.3 ● ● ■ Uchibō Line (some through services)

Rolling stock

Local service

Keiyō Line through service

Between Soga and Katsuura:

Sōbu Line (Rapid) through service

Between Chiba and Kazusa-Ichinomiya:

Wakashio Limited Express

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)[2]

History

Mobara handcar line
A former handcar converted with a petrol engine at Ohara

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 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 9 km (5.6 mi), 610 mm (2 ft) gauge handcar line to Tai Muko between 1909 and 1924. The council then decided to build a railway to connect to the Kominato Line. 12 km (7.5 mi) of 1,067 mm (3 ft 6 in) gauge line was opened as far as Okuno between 1930 and 1933, the first 6 km (3.7 mi) 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 16 km (9.9 mi), 610 mm (2 ft) gauge handcar 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.[3]

References

  1. ^ "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 15 April 2024.
  2. ^ "10/21, 房総211系, 営業運転開始" [Boso 211 series enter service]. Japan Railfan Magazine (in Japanese). Vol. 47, no. 549. Japan: Koyusha Co., Ltd. January 2007. p. 179.
  3. ^ "ほぼ直線…外房線先頭車両が脱線 原因は？". headlines.yahoo.co.jp (in Japanese). 8 May 2020. Retrieved 9 May 2020.

External links

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