6943 The two diesel cars KIHA 120-314 and KIHA 120-309 crossing the Gônokawa River at Ozekiyama near Miyoshi. (2017)
On April 1, 2018, the Sankô-sen closed completely. The line could be seen as part of a connection between the Japan Sea (the San'in region) and the Inland Sea (the San'yô region), but in fact it did not link the centres of the San'in (Matsue, Izumo or Hamada) with the centres of the San'yô (Okayama, Fukuyama, Hiroshima) in an attractive way.
The Sankô-sen provided a regional service from the plateau of Miyoshi in the mountains of Hiroshima prefecture (157 metres above sea level) all along the river Gô-no-kawa down to the Japan Sea coast and the Gô-no-kawa estuary at Gôtsu (9 m.a.s.l.). On its way, it crossed the border between the Hiroshima and Shimane prefectures. The total length of the line was 108, 1 km, which is considerably longer than the direct distance of around 60 km between Miyoshi and Gôtsu.
Before closure there were only few services on the Sankô-sen, and these stopped at all stations, which made the full journey very slow. The line was not electrified. There was one through train in both directions in the morning, starting before 6 o'clock, and one more through service in the mid-afternoon. Three more services linked Gôtsu with Hamahara, 50, 1 km up the line; one of these ran to and from Hamada on the Japan Sea coast, where the diesel cars were serviced. There were two additional services both ways between Hamahara and Miyoshi in the very early morning and in the evening, and one train ran between Kuchiba (79, 7 km up the line) and Miyoshi and return in the afternoon.
Construction of the northern part of the Sankô-sen up the valley commenced in 1930 and reached Hamahara from Gôtsu in 1937. The southern part from Miyoshi down the valley as far as Kuchiba opened between 1955 and 1963. These two sections can be termed the "old line", which sees a maximum speed of 65 km/h. Work on the link between Kuchiba and Hamahara (the "new line", with a maximum speed of 85 km/h) began in 1966 and was completed in 1975. Through running between Miyoshi and Gôtsu became possible as from 1978. In 1982 freight services ceased. In spite of the maximum speeds possible (65 and 85 km/h), there were many sections which could only be traversed at speeds of between 15 and 30 km/h, depending on the weather conditions.
Torrential rain, landslides, flooding and fallen trees affected operation of the line from the outset. In recent years the line has been interrupted
- from July 11, 1972 to December 29, 1974 (Akatsuka to Hamahara closed)
- from July 23, to September 12, 1983
- from July 19, 2006 to June 16, 2007 (at first complete closure; December 15, 2006 Hamahara – Miyoshi reopened),
- from August 1 to 12, 2013 (Iwami Kawamoto – Hamahara),
- from August 24, 2013 to July 19, 2014 (at first complete closure; September 1, 2013, Hamahara-Miyoshi reopened).
Due to heavy snowfall and fallen trees the line was closed as from January 19, 2018, between Iwami Kawamoto and Miyoshi, but reopened up the valley as far as Hamahara on February 2.
The population along the line is dwindling continuously, and with increased motorisation we see a fall of passengers carried from an average of 458 persons per day in 1987 to 44 per day in 2013. Since then there has been a slight rise due to visitors to the line in view of closure.
In 2015, local organisations began to do their best to market the line, and indeed there have been all kinds of innovative plans to attract and welcome visitors. However, JR West saw no future for the railway, and the re-occurring natural disasters leading to partial or complete closure of the line for long periods led to the decision to abandon the Sankô-sen. There are various plans to re-use some of the infrastructure as monuments or to create a railway park "Gô-no-kawa Tetsudô" ("Gô-no-kawa Railway") in and around Kuchiba / Uzui.
At present (2022) short runs can be made in little tourist railway trucks from Kuchiba station upwards, and visits to the elevated Uzui station are also possible.
The name of the line derives from its two endpoints, Miyoshi (written 三次 ) and Gôtsu (written 江津 ). The two characters 三 and 江 together are read "Sankô").
1 Ozekiyama 尾関山 2 Awaya 粟屋 3 Nagatani 長谷 4 Funasa 船佐 5 Tokorogi 所木
6 Nobuki 信木 7 Shikijiki 式敷 8 Kôyodo 香淀 9 Sakugiguchi 作木口 10 Gôbira 江平
11 Kuchiba 口羽 12 Ikawashi 伊賀和志 13 Uzui 宇都井 14 Iwami Tsuga 石見都賀
15 Iwami Matsubara 石見松原 16 Ushio 潮 17 Sawadani 沢谷
18 Hamahara 浜原 19 Kasubuchi 粕淵 20 Akatsuka 明塚 21 Iwami Yanaze 石見簗瀬
22 Onbara 乙原 23 Take 竹 24 Kirohara 木路原 25 Iwami Kawamoto 石見川本
26 Inbara 因原 27 Shikaga 鹿賀 28 Iwami Kawagoe 石見川越 29 Tazu 田津
30 Kawado 川戸 31 Kawahira 川平 32 Chigane 千金 33 Gôtsu Honmachi 江津本町