[1] In 1917, the Chosen Government Railway's (Sentetsu) Hamgyeong Line reached Hoeryeong.

[3] The narrow-gauge Tiantu Railway (天圖鐵道, Chinese pinyin: Tiāntú Tiědào; Japanese: Tento Tetsudō), opened in 1923, signed a cross-border operational agreement with the Domun Railway on 26 June 1926,[4] after which a bridge across the Tumen River between Sangsambong and Kaishantun was opened on 30 September 1927.

[1] The line at once became a very important link between Japan and the Asian mainland via the Korean port of Rajin.

In 1940 there were seven passenger trains between Chaoyangchuan and Sambong and eight from Sambong to Chaoyanghcuan, with a second-class ticket for the full distance costing 1 Manchukuo yuan 8 chiao 3 fen, and a third-class ticket costing 1 yuan 1 chiao.

[9] By the time the last timetable was issued prior to the start of the Pacific War in November 1942, service on the line had been cut back to three return trips between Chaoyangchuan and Sambong – one each in the morning, afternoon, and evening.