[1] On 21 June 1940, the West Chosen Central Railway, which since 1939 had been operating a line between Sŭnghori and P'yŏngnam Kangdong,[2] received approval from the Railway Bureau of the Government-General of Korea to build a line to the Changsang coal fields via Tŏkch'ŏn;[3] the Chosen Anthracite Company had opened mines around Changsang and Tŏkch'ŏn in 1938[4] From Tŏkch'ŏn, which it had reached in the summer of 1945, the West Chosen Central Railway planned its Tŏkpal Line (덕팔선; 德八線) line to run from Tŏkch'ŏn to Kujang via Changsangri (today's Changsang Station), to connect there with the Chosen Government Railway's Manp'o Line.

However, the terrain proved too difficult, and, after adding a signal station at Hyangjang between Hyangwŏn and Changsangri, construction on the current alignment of the line to Kujang began.

However, this wasn't completed before the end of the Pacific War, and it was only after the end of the Korean War that the connection to Kujang and the Manp'o Line was finally made.

[5] After the partition of Korea following Japan's defeat in the war, all railways in North Korea were nationalised and made part of the Korean State Railway.

[5] A yellow background in the "Distance" box indicates that section of the line is not electrified.