Chashan Tunnel

Completed in 1901 after two years of work plagued by groundwater intrusion, collapses, and disease, this 439 meter-long, curved passage was the only tunnel on the Japanese colonial era line that replaced the Qing dynasty route between Taipei and Taoyuan. Steep grades and the declining flow of the Dakekan River (大嵙崁溪) made a riverside realignment feasible, and the tunnel was abandoned in 1926 after only 25 years of service, thereafter serving as fuel and supplies storage for the Japanese military. A road cut over the hill in 1933, now Highway 114, hid the entrances from view; construction of an incinerator in 1995 buried the northern portal, and widening works completed in 2002 sealed the southern one in concrete, leaving a two storey guard post and a stone bridge pier at Anankeng (阿南坑) as the only surface traces. A close inspection of the southern entrance might reveal some brickwork at the surface, but the precise location is increasingly lost in time.