[2] As freight movements between the east and west coasts of the DPRK grew in the years after the end of the Korean War, congestion on the P'yŏngra Line became a major issue.

To relieve this, the Korean State Railway undertook the construction of a third, more southern transversal line through the mountainous south-central region of the DPRK.

Grain from the rich granary of Hwanghae is shipped east exclusively along this line, whilst the westbound ore is primarily magnetite from the Tŏksŏng and Musan Mining Complexes destined for the Hwanghae Iron & Steel Complex on the Songrim Line.

[5] In the 2002 passenger timetable there is a single daily long-distance train shown as operating on this line, between Haeju and Hyesan.

Train 104•107 from Haeju comes to the line via Sariwŏn, departing P'yŏngsan at 0:54 and Sep'o at 6:06 AM, continuing on to Hyesan via Wŏnsan, Hamhŭng and Kilju.