SYDNEY'S AIRPORT RAIL

The 10km long New Southern Railway section of the railway system in Sydney, Australia has five new railway stations, links the city centre with the international airport, and is almost all underground. This article describes its construction, which began in December 1995, and is scheduled for completion in mid-2000. It is financed by a combination of public and private sector funding. The four sections of the line are: (1) a short section of cut-and-cover tunnel; (2) the 2.4km 'rock tunnel' section, mainly through sandstone, being drilled by a Voest Alpine AM-105 roadheader; (3) 5.8km through water-bearing sands, silts, and clays, to be excavated by a slurry-based Herrenknecht Mixshield tunnel boring machine (TBM); and (4) 1.8km to be constructed by staged phases of cut-and-cover work. All four underground stations will have open box construction. The underground alignment is based on the single-tube double-track concept, with tunnels of large diameters and cross-sections.