[2] Shortly thereafter, the West Chōsen Development Railway was set up to take over this line, which it did on 21 April of the following year.

[3] Immediately after that, the West Chōsen Development Railway began work on another narrow gauge line, a 21.5 km (13.4 mi) line from Sariwon to Jaeryeong via Sanghae, opening it on 21 December 1920,[4] and on 16 November of the following year it was extended from Jaeryeong to Sincheon, a distance of 13.6 km (8.5 mi).

The northwestern area was not left ignored, as just over a month later, a 17.7 km (11.0 mi) extension from Sugyo to Jangyeon was opened on 21 January 1937.

[20] After the end of the Korean War, the entirety of the former Hwanghae Line network was within North Korea.

[19] In the November 1942 timetable, the last issued prior to the start of the Pacific War, Chōtetsu operated an extensive schedule of third-class-only local passenger services:[1]