Hamgyong line

The Hamgyeong Line was a railway line of the Chosen Government Railway (Sentetsu) in Japanese-occupied Korea, running from Wonsan to Sangsambong. Construction began in 1914, and was completed in 1928. The line is now entirely within North Korea; the Korean State Railway has divided it between the Kangwŏn Line (Wonsan−Kowon section), the P'yŏngra Line (Kowon−Cheongjin section), the Kangdŏk Line (Namgangdŏk−Suseong), and the Hambuk Line (Chongjin−Sangsambong section).

History
Sentetsu began construction of a line north from Wonsan on the Gyeongwon Line on 1 October 1914. The first section, a 20.0 km line from Wonsan to Muncheon, was completed on 1 August 1915, followed by a 34.4 km extension from Muncheon to Yeongheung via Gowon on 21 July 1916. At the same time, Sentetsu started construction of a line north from the important east coast port of Cheongjin, completing the first 55.7 km section from Cheongjin to Changpyeong, on 5 November 1916.

On 31 July 1917, the management of Sentetsu was transferred from the Railway Bureau of the Government-General of Korea to the South Manchuria Railway (Mantetsu), which established the Mantetsu Gyeongseong Railway Administration (Japanese: 満鉄京城管理局, Mantetsu Keijō Kanrikyoku;, Mancheol Gyeongseong Gwalliguk) to oversee the operation of all railways in Korea. Construction of the Cheongjin Line was accelerated under Mantetsu management, and by the end of 1917 it had been completed all the way to Hoeryeong, with the 13.4 km from Changpyeong to Pungsan opened on 16 September, and the remaining 24.7 km to Hoeryong opened on 25 November of that year.

To handle increasing freight traffic on the line, a large marshalling yard, called Cheongjin Jochajang, was built near Cheongjin. To access this, a new 14.9 km line between Nanam and Suseong (on the Cheongjin−Changpyeong line) was built, being opened on 10 December 1919; Gangdeok Station, located 7.2 km from Nanam, was opened on 1 August 1922. Construction of the southern portion of the Hamgyeong Line continued at the same time, with a new 69.5 km section from Yeongheung to Hamheung being opened on 15 December 1919.

Mantetsu continued expanding the Hamgyeong Line slowly over the next few years, opening 21.0 km south from Nanam to Jueul on 11 November 1920, 18.0 km north from Hamheung to Seohojin on 1 December 1922, followed by another 18.4 km north from Seohojin to Toejo on 25 September 1923. Following that three-year period of rather sedate expansion, on 11 October 1924 Mantetsu opened three major new sections: 58.0 km north from Teojo to Yanghwa, 39.5 km south from Jueul to Ponggang, as well as a disconnected, 84.7 km central section from Dancheon to Gilju.

On 1 April 1925, management of Korea's railways was returned to the Railway Bureau, and Sentetsu became independent of Mantetsu once again. Construction of the east coast line slowed down somewhat for a time, with 1925 seeing the opening of only 14.1 km of new line (Yanghwa−Sokhu), whilst in 1926 only 26.2 km of new construction was completed - 8.9 km north from Sokhu to Sinbukcheong, and 17.3 km south from Ponggang to Geukdong. The first half of 1927 was even slower - only an 8.1 km section from Geukdong to Yongdong had been completed by 10 June; in the second half of the year, however, major progress was made, with over 85 km of new railway opened: 39.4 km from Gilju to Yongdong, 31.5 km from Gunseon to Dancheon, as well as a section of approximately 15 km from Sinbukcheong to Bansong (this station, located somewhere between Geosan and Geonja, was closed on 31 August 1928.

The final 26.1 km gap between Geosan and Gunseon was closed on 1 September 1928, completing the line in its entirety from Wonsan to Hoeryeong. At the same time, the line was split, with the Wonsan−Cheongjin section being named the Hamgyeong Main Line, and the Cheongjin−Hoeryeong section becoming the Cheongjin Line. These lines later played a major role in the Japanese invasion of Manchuria, and grew further in importance after the establishment of the puppet state of Manchukuo.

The privately owned Domun Railway was formed in 1920, opening its first line, (40.4 km) from Hoeryeong to Sangsambong on 5 January 1920. This line was subsequently extended twice, from Sangsambong to Jongseon (9.1 km) on 1 December 1922, and from Jongseon to Donggwanjin (8.2 km) on 1 November 1924.

In order to create the shortest possible route from Japan to eastern Manchuria, Sentetsu began construction of a line from Unggi (now Sŏnbong) to Donggwanjin via Namyang in 1929. Named the East Domun Line, it reached Donggwanjin on 1 August 1933, at which time the entire Hoeryeong−Unggi line was redesignated as the Domun Line, and Donggwanjin Station was renamed to Donggwan Station.

On 1 April 1929, the Domun Railway was nationalised, with the mainline becoming Sentetsu's West Domun Line, after which the Manchukuo National bought the Tiantu Railway, converting it to standard gauge and opening the new line, called Chaokai Line, at the end of March 1934, creating a second direct connection across the Tumen River between Korea and Manchukuo.

Just a few months after completion of the line from Unggi, on 1 October 1933 the management of Sentetsu's entire route from Cheongjin to Unggi was transferred to Mantetsu,. On 1 November 1934, Mantetsu rearranged these lines, merging the Namyang Border Line with the Unggi−Namyang section of the Domun Line to create the North Chosen East Line (Unggi–Namyang–Tumen), with the Namyang–Sambong section becoming the North Chosen West Line. In 1936, the "Asahi" express train between Xinjing and Najin was inaugurated, to connect to the ferry from Najin to Japan.

In 1940, management of the Cheongjin–Sangsambong route was transferred back to Sentetsu, merging it with the Wonsan−Cheongjin Hamgyeong Main Line to create the Hamgyeong Line; Mantetsu continued to manage the North Chosen Line, eventually acquiring outright ownership of the line.

On 1 December 1941, a new line was opened between Nanam and Cheongjin to allow trains to bypass the Cheongjin marshalling yard. The existing line, running via Gangdeok Station and the marshalling yard, was detached from the Hamgyeong Line and designated the Gangdeok Line; at the same time, a 2.4 km connection from Cheongjin Seohang Station (Cheongjin West Port) to Gangdeok was built, to allow southbound trains to access the marshalling yard without having to reverse at Nanam. Later, the Cheongjin−Changpyeong line was realigned, reducing the distance from Cheongjin to Suseong from 9.0 km to 7.8 km; this work was completed on 1 February 1942.

Service on the line was suspended after the Soviet invasion at the end of the Pacific War. The damage sustained by the line during the war was slow to be repaired due to strained relations between the Soviets and the Korean People's Committees; those two bridges have not been repaired to the present day. After the partition of Korea, the Provisional People’s Committee for North Korea nationalised all railways in the Soviet zone of occupation on 10 August 1946, and following the establishment of the DPRK, the Korean State Railway was created in 1948. After the end of the Korean War, the North Korean railway system was restructured, which included the rearrangement of several rail lines. This included the division of the Hamgyeong Line into three parts.

The Cheongjin−Hoeryeong–Sambong (formerly Sangsambong) section of the Hamgyeong Line inherited from Sentetsu was merged with the former Sambong−Namyang North Chosen West Line, the Namyang−Unggi section of the North Chosen East Line, and the Unggi−Najin Ungna Line inherited from Mantetsu to create the new Hambuk Line running from Cheongjin to Najin via Namyang. The Namyang−Tumen cross-border section of the North Chosen East Line was split off to create the Namyang Gukgyeong Line.

The Gowon−Geumya (formerly Yeongheung) section of the Hamgyeong Line was merged with the Pyeongyang−Gowon Pyeongwon Line and the partially completed Cheongjin−Rajin Cheongna Line to create the P'yŏngra Line from Pyeongyang to Najin.

The partition of Korea left the Pyeonggang−Wonsan section of Sentetsu's Gyeongwon Line in the DPRK; this was then merged with the Wonsan−Gowon section of the former Hamgyeong line to create the Pyeonggang−Wonsan−Gowon Kangwŏn Line.