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.
Korean Peninsula
Until the end of World War II, Korea was a single political entity whose territory roughly coincided with the Korean Peninsula. In August 1945, the Soviet Union declared war on Imperial Japan, as a result of an agreement with the United States, and liberated Korea north of the 38th parallel. U.S. forces subsequently moved into the south. By 1948, as a product of the Cold War between the Soviet Union and the United States, Korea was divided into two regions, with separate governments. Both claimed to be the legitimate government of all of Korea, and neither accepted the border as permanent. The conflict escalated into open warfare when North Korean forces—supported by the Soviet Union and China—moved into the south on 25 June 1950. Since the ended the Korean War in 1953, the northern section of the peninsula has been governed by the Democratic People's Republic of Korea, while the southern portion has been governed by the Republic of Korea.