Taipei Railway Underground Project

The Taipei Railway Underground Project is an ongoing project in Taipei, Taiwan to remove surface railway facilities, replacing them with a 22.5 kilometres (14.0 mi) tunnel and new facilities outside the city limits. The underground section includes separate tunnels for the 3 ft 6 in (1,067 mm) tracks of national rail carrier Taiwan Railway Administration's (TRA) Western Line and for the Standard gauge tracks of Taiwan High Speed Rail Corporation (THSRC). All stations on the section are rebuilt as multi-level complexes, which also function as transport hubs, with underground platforms for TRA and THSRC trains, and new stations of the Taipei Metro at deeper levels.

In the early 1980s, railway facilities in central Taipei were seen as obstacles to rail traffic and local development, and were seen as bad for the city's appearance. Therefore, the executive branch of Taiwan's government, the Executive Yuan, tasked the Taipei Railway Underground Project Organisation (TRUPO) with the project to rebuild railway facilities.

The first phase of the project was the complete reconstruction of Taipei Main Station as a multi-level building, with train platforms placed underground along with adjacent tracks. Work on the 4.42 km (2.75 mi) section between Huashan and Wanhua began in July 1983, and was completed after NT$17.792 billion spent in September 1989.

In the nineties, the tunnel was extended both eastward and westward, and with separate double track north and south tunnels, preparation was made for Taiwan High Speed Rail, the planned high-speed line to Kaohsiung. The eastward extension, the Songshan Project, added 5.33 km (3.31 mi) to Songshan. The project cost NT$27.48 billion, and was in construction from July 1989 until June 1994. On the surface, the space gained was used for the construction of the elevated Civic Blvd Expressway, which opened in September 1997.

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