[1] It is an important line in economic terms, connecting the agricultural and ore-producing areas of Kwail and Ŭnnyul counties with the rest of the DPRK.

[2] The West Chosen Development Railway (西鮮殖産鉄道, Seisen Shokusan Tetsudō; 서선식산철도 Sŏsŏn Siksan Ch'ŏldo) was formed in 1920 to take over the 762 mm (30.0 in) narrow gauge Sanghae—Hwasan—Naet'o line built by the Mitsubishi Ironworks as a company-use railway,[3][4] and then built a new narrow gauge line from Sariwŏn to Chaeryŏng via Sanghae.

After the end of Japanese rule and the subsequent partition of Korea, Sentetsu's Changyŏn Line was located in the northern half, becoming part of the Korean State Railway.

After the end of the Korean War the Railway Ministry of the DPRK began to expand and improve its network, including in South Hwanghae, leading to the opening of a line from Sugyo to Ch'ŏlgwang in 1963.

[2] In terms of traffic quantity, freight on the Ŭnp'a–Sugyo section is roughly the same in both directions, but the bulk of freight on the Sugyo–Ch'ŏlgwang section is iron ore eastbound from the Ch'ŏlgwang area destined for the Hwanghae Iron & Steel Complex on the Songrim Line.