In order to exploit the rich iron deposits of the Musan region, the North Chosen Colonial Railway began construction of this line, calling it the Hambuk Line. The line was opened in two parts - the Komusan-Sinch'am section opening on 20 August 1927, and the Sinch'am-Musan segment being opened on 15 November 1929. On 1 February 1937, Musan Ch'ŏlsan station was opened. Originally built as a narrow-gauge line, the conversion to standard gauge was completed on 1 May 1940, and the extension to Musan Kangan station was completed then as well. By 1942, the North Chosen Colonial Railway was operating four daily return trips between Komusan and Musan, timed to connect with local and express services on the Chosen Government Railway's Hamgyŏng Line. On 1 April 1944, the line was absorbed into Sentetsu; at the same time, the line was given its current name, Musan Line, and the extension to Musan Kangan station was closed. In order to facilitate the transport of ironstone from the Musan Mining Complex, the 33.6 km section between Sinch'am and Komusan was double-tracked, and electrification of the line was completed in 1977.
Services
Freight
Freight traffic on the Musan Line is 7.5 times greater in the eastbound direction than the reverse. 94.2% of the freight moved towards Komusan is magnetite ore from the Musan Mining Complex; timber accounts for 4.3%. From Komusan to Musan coal forms the majority of freight, along with other necessities - grain, fertiliser, cement etc. A large portion of westbound trains consist of empty cars bound for the mines at Musan. Most freight traffic on the line is from the Musan Mining Complex via the Musan Mining Line to the Kim Chaek Steel Complex, the Ch'ŏngjin Steel Works, the Sŏngjin Steel Complex and export goods to Namyang Station for forwarding to China.
Express trains9/10, operating between P'yŏngyang and Musan, run along the entirety of this line between Komusan and Musan;
Two daily pairs of local trains, 662/663 and 668/669, operate between Musan and Chuch'o.
There are also local trains running between Musan and Ch'ŏngjin at the southern junction of the Hambuk and P'yŏngra Lines. Further, there are several daily commuter trains for workers between Musan and Ch'ŏlsong and for students between Musan and Komusan.
Route
A yellow background in the "Distance" box indicates that section of the line is not electrified.
