On 13 May 1916 the Mitsui Mining Railway (Korean: 미츠이 광산 전용 철도; MR: Mich'ŭi Kwangsan Chŏn'yong Ch'ŏldo; 三井鉱山専用鉄道, Mitsui Kōzan Sen'yō Tetsudō) opened its first railway line, a 29.5 km (18.3 mi) 762 mm (2 ft 6.0 in) narrow-gauge line from Gaecheon to Sinanju, where it connected with the Chosen Government Railway's (Sentetsu) Gyeongseong−Sinuiju mainline, the Gyeongui Line.

The Mitsui Railway subsequently extended its line with a 6.3 km (3.9 mi) section from Gaecheon to Cheondong, which was opened on 1 December 1918.

[4] The Korean State Railway began the regauging work in March 1949, completing it in eight months.

[5] In the November 1942 timetable, the last issued prior to the start of the Pacific War, Sentetsu - which by then had absorbed the Gaecheon Light Railway - was running six round trip passenger trains, third-class only, between Sinanju and Gaecheon daily; the 29.5 km (18.3 mi) trip was scheduled to take one hour and twenty-five minutes, and a ticket for the entire distance cost 60 sen.[6] Little information is available about the specifics of the locomotives and rolling stock used by the Gaecheon Light Railway.

1 was originally built by the Baldwin Locomotive Works of the United States for the South Manchuria Railway, which used it on the Anpo Line prior to its conversion to standard gauge; after the regauging of the line was complete, the engine was transferred to the Gaecheon Light Railway.