Balfour Beatty Rail has won contracts for the trackwork and third rail for the Santiago Metro Line 4, worth US$70M. Line 4 is 24.1km long and the spur Line 4A is 7.7km long, both are planned to be brought into operation by late 2005.
The client, Santiago Metro, is an offshoot of the Ministry of Transport and engaged Systra for conceptual design and technical services relating to the rail system. The scheme is being financed with Santiago Metro’s own resources and a bond issue on the New York Stock Exchange to raise funds.
The NATM tunnels were driven through clay and gravels. Lattice arches at 1m intervals were used with shotcrete infill. Between stations, the tunnels are oval in profile, with dimensions in the region of 11m x 8.4m, stations were constructed with a face area of approximately 65m2. Driven predominantly by local contractors, a typical contract consists of 1.2km of tunnel plus two stations.
