Gyeongui Line (1904–1945)
Following Japan's defeat in the Pacific War and the subsequent partition of Korea, the Gyeongui Line was divided at the 38th parallel between North and South Korea. On 25 August 1945, the Soviet Army began operating trains on the line north of Sariwon, whilst trains in the south terminated at Gaeseong. In 1946, the railways in both North and South were nationalised, creating the Korean National Railroad in the South and the Korean State Railway in the North. After the Korean War, the Gyeongui Line was split into three sections. In the South, the Seoul–Jangdan section became the KNR's Gyeongui Line, retaining the same name; in the North, the Bongdong–Pyeongyang section became the P'yŏngbu Line, whilst the Pyeongyang–Sinuiju section became the P'yŏngŭi Line.
Division of Korea
In December 1945, at the Moscow Conference, the Allies agreed that the Soviet Union, the US, the Republic of China, and Britain would take part in a trusteeship over Korea for up to five years in the lead-up to independence. Many Koreans demanded independence immediately; however, the Korean Communist Party, which was closely aligned with the Soviet Communist party, supported the trusteeship. According to journalist Fyodor Tertitskiy, documentation from 1945 suggests the Soviet government had no plans for a permanent division.