From a point of about 1,600 m, the tracks of the Kosei Line intersects the tracks of the Biwako Line, and Kosei Line tracks (westbound and eastbound) proceed toward portals for westbound and eastbound located about 1,750 m from this point, with a gradient of -11 for eastbound, and a gradient of 1 for westbound.
約1,600m離れた位置からは、湖西線と琵琶湖線の線路が交差し、湖西線下り線は下り11、湖西線上り線は上り1となり、約1,750m離れた位置に湖西線下り線・上り線のトンネル入口がある。