[1] 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 new narrow-gauge line from Sugyo to Ch'ŏlgwang in 1963.

In 1964, another new narrow-gauge line was opened from Ch'ŏlgwang, to serve the iron ore mines around Sŏhaeri and the port at Ryongjŏng.

[3] In 1971, a new standard gauge line was opened from Ŭnp'a on the former Sahae Line to Chaeryŏng, and at the same time, the Chaeryŏng—Sinch'ŏn—Sugyo section was converted to standard gauge.

At its peak the line carried 6,000 tonnes of ore daily.

[3] The orange background in the "Distance" box indicates that section of the line is not electrified narrow-gauge.