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.
Second Phase Offensive
The Chinese were pleased with the outcome of their Second Phase Offensive, having regained nearly all of North Korea from U.S./UN forces. However, the Chinese victory created the opinion among Chinese leaders that "we can defeat American armed forces." As a consequence of this confidence, the Chinese soon launched offensives into South Korea that would be turned back by the U.S./UN. By Spring 1951, the Korean War had turned into a stalemate and China had given up carrying out large-scale offensives. On July 27, 1953, after lengthy negotiations, the U.S./UN, North Korea, and China signed the Korean Armistice Agreement, halting the Korean War with the border between North and South Korea roughly the same as it had been before the war. China slowly withdrew its forces from North Korea, the last leaving by October 25, 1958. The United States retained a military force in South Korea which in 2018 numbered 23,000.