Tunnel with arched shape between Kuriyama station and Kurigaoka station on Muroran Main Line. This track was once a double track, but in 1990 (Heisei 2), "Kuriyama tunnel" in the down line section was Because it collapsed due to landslides, now it is only a single track (up line). The restoration of this tunnel is not currently being carried out, and it remains neglected.