This line has steep gradients and long tunnel sections, as the line was originally built to shorten the Sanyō Main Line along the old San'yōdō. It runs more closely parallel to the Sanyō Shinkansen than the Sanyō Main Line.
Morigahara Junction (森ヶ原信号場,Morigahara Shingōjō?) between Kawanishi and Hashirano Stations is the point where the Nishikigawa Seiryū Line diverges from the Gantoku Line. Between this junction and Kawanishi Station, the two lines share the same track.