Seoul Metro
In 1974, Seoul Subway Line 1, the first rapid transit system in South Korea, was opened. Lines 2-9 would be opened later. Lines 1, 3, and 4 are operated by Korail and Seoul Metro, while lines 5-8 are operated by SMRT. Line 2 and Line 9 are operated by Seoul Metro. Korail operates the Bundang, Jungang, and Gyeongui lines.