The Pinghsi Line was originally a coal-hauling railway, built in 1918 by the Taiyo Mining Corporation. Starting at the Santiaoling Station in Ilan County, its terminus is at Chingtung Station, giving it a length of 12.9 kilometers. In 1929 the Japanese colonial authorities brought the line under government authority, and began passenger service.
平溪線原為礦業鐵道，民國七年由「台陽礦業公司」修築啟用，起於宜蘭縣鐵路的三貂嶺站，終點為菁桐站，全長十二・九公里，原先以運煤為主，民國十八年日據時代將平溪線改為官營，始有客運服務。