Old Mountain Line - Da'an River Iron Bridge Introduction
The "Old Mountain Line - Daan River Bridge" is located on the border between Taichung and Miaoli, adjacent to the southern entrance of the No. 7 Tunnel in Sanyi, Miaoli County, and the Houli District of Taichung City. It has a total length of 637.39 meters and comprises 8 trusses, constructed with 10 spans of 62.41 meters (each span between two piers is counted as one). The Daan River Bridge was built in the 36th year of the Meiji era (1903) and completed in the 41st year of the Meiji era (1908). It was an important bridge for transporting goods and connecting the north and south during the Japanese occupation. The Daan River Bridge was rebuilt after the Central Taiwan Earthquake in the 10th year of the Showa era (1935). In the 52nd year of the Republic of China (1963), to enhance the bridge structure so that it could support heavier, faster, and more frequent trains, a steel beam replacement project was carried out. Although it is not the original structure, its appearance seems similar to the original construction, with only slight differences in the trusses and connections. After the Old Mountain Line ceased operations in the 87th year of the Republic of China (1998), no trains have run over the Daan River Bridge. Currently, on the Old Mountain Line of Taiwan Railway, there are only three iron bridges with this type of steel bridge structure: Daan River Bridge (637.39 meters), Dajia River Bridge (382.2 meters), and Gaoping River Old Iron Bridge (1,526 meters). Due to the good preservation of the Daan River Bridge, a project for the digitization of old photographs of the Old Mountain Line's potential World Heritage Site was carried out in the 93rd year of the Republic of China (2004). After being reorganized in the 99th year of the Republic of China (2010), it was combined with the revival of steam trains on the Old Mountain Line. In the 105th year of the Republic of China (2016), a "Research Study and Preservation and Management Principles Plan for the Railway Cultural Landscape of the Old Mountain Line" was executed. It is now managed with restricted access for tourist safety.
