The Seaford Rail Extension in South Australia
by Rob Shaw (Rob)
In a state where railway closures have become more common than expansion, construction of a 5.7 kilometre, dual track extension of South Australia's Adelaide to Noarlunga line is steadily taking shape. Federal funding of $291 million was contributed to the project and major construction commenced in January 2011.
Three newly completed road bridges now convey traffic over the future right of way, and a 1.2km viaduct over the Onkaparinga River valley will soon displace the Algebuckina bridge in the state's north as South Australia's longest railway bridge; and will be 200m longer than the Swanport Bridge which carries Highway 1 over the River Murray.
Twenty one concrete spans are being fabricated on site and pushed into position from each end using steel launching noses christened by students from the local Noarlunga Downs Primary School. The "Silva Snozzle Bright" works away from the southern abutment, while "Bluey Bluey Bignose" eases out the spans which reach from the northern side of the tidal estuary.
South of the viaduct tracks return to the alignment of the former Willunga branch, which was closed from Hallet Cove onwards in 1969 and perhaps prematurely dismantled in 1972.
In 2009, the state government began undertaking the biggest rehabilitation of the state's broad gauge commuter network since the "Webb era" of the 1920's. Redevelopement has seen Adelaide's metropolitan lines relaid with improved roadbed and drainage, gauge convertible concrete sleepers, and upgrades to several stations. Plans include the installation of 25kV AC power systems on all but the Belair line, where tunnel clearances cannot accommodate overhead electrification.
Work on the Seaford extension is expected to be complete in 2013, coinciding with the completion of the Noarlunga line's overhead electrification. A new railcar depot under construction south of the Onkaparinga River will service the state's first electric trains, and the Noarlunga to Seaford section will be used for commissioning and testing of the system prior to opening for revenue service.