The Sillim Line on the Seoul subway serves 11 stations over roughly 6.9 km. It runs between Gwanaksan and Saetgang. Its earliest stations opened in 1974. It interchanges with 4 other lines.
Length estimated from station coordinates, accurate to a few hundred metres.
These maps and lists cover Lines 1 to 9 plus the Ui LRT and Sillim Line. The Korail commuter services (Gyeongui-Jungang, Suin-Bundang), AREX and the Shinbundang Line are not included. The game itself only asks about stations in Seoul and its immediate ring.