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.
Gyeongwon Line
After the partition of Korea following the end of the Pacific War in 1945, the Gyeongwon Line was split along the 38th parallel between the stations of Hantangang and Choseongni. The railways in both South and North were nationalised, and the newly-established Korean National Railroad took over operation of the truncated Gyeongwon Line, from Seoul to Choseongni; in the North, the Korean State Railway merged its section of the Gyeongwon Line, Choseong-ri−Wonsan, with the Wonsan−Gowon section of the former Hamgyeong Line to create the Gangwon Line.