Not sure if it’s quad tracked between Seoul Station and Cheongnyangni Station but if it’s double tracked is there a limit between those 2 stations? Also still unsure how far the Seoul Metro train cars are operated if the Korail cars are operated along the lines entirety. Always for some reason thought the Metro train cars were ran between Seoul and Cheongnyangni Stations since that section is considered the “subway” subway especially in terms of electrification. Also does the same apply for Lines 3 and 4 with subway trains turning back right before the Korail sections? It’s more understandable in that case since the subway section is much longer than 10 stations.