Nearly 5-km of the 15-km underground route of the Gautrain has been completed.
The underground route of the R25-billion Gautrain project stretches from Johannesburg Park station, under the Johannesburg Hospital, Parktown Ridge, Rosebank, Sandton and Marlboro, to where it sur- faces at the Marlboro portal. There are a number of emergency shafts en route.

A section of the 3-km tunnel between Park station and Rosebank station is being excavated using a high-technology tunnel boring machine. The remainder of the tunnels are being built by traditional drill and blast technology.

Here is a visual update on the 80-km project, which will connect, Johannesburg, Tshwane and OR Tambo International Airport by 2011. It is a public–private partnership between the Gauteng government and the Bombela consortium.GTTraindepotofficesmaintenanceyard05-08.JPG

PARK STATION

Excavation of the single-track rail tunnel towards emergency shaft two in Houghton has reached about 310 m. Construction of the underground station box and multistorey parkade foundation is making good progress. Within the station box, waler beams and struts have been installed to provide temporary lateral support to the perimeter walls during station box excavation 

TUNNEL BORING MACHINE

The giant tunnel boring machine (TBM) has already installed about 460 tunnel-lining segment rings in the single-track rail tunnel being build towards emergency shaft two. This equates to a distance of almost 690 m of tunnel bored below Oxford road. The TBM installs precast concrete tunnel-lining segments behind it as it moves forward. It leaves behind a watertight and smooth lining to the 6,8 m diameter tunnel. Seen here are some of the precast segments waiting to be installed 

EMERGENCY SHAFT 5 (DUNKELD, ROSEBANK)

The tunnel going southwards towards Sandton station has progressed to about 315 m. Excavation of a safe haven chamber for commuters is being constructed simultaneously. A structure above emergency shaft five houses the overhead gantry crane. This is used for hoisting excavated rock, and lowering and lifting materials and equipment. The crane is clad with sound-absorbing panels to limit noise created by construction work.This is a temporary structure, which will be removed once tunnelling operations are completed

VIADUCT THREE

A continuous long-span elevated rail bridge is called a viaduct. Several viaducts are being built to cross rivers and roads on the Gautrain route. Construction of viaduct three over Allandale Road is making good progress 

DEPOT, PRECAST YARD AND RAIL WELDING FACILITY

At the train depot, Gautrain's 24 train sets will be maintained, serviced, cleaned, and securely stabled overnight. The adjacent bus depot will perform a similar function for Gautrain's dedicated fleet of 150 luxury buses. Construction of these facilities is well advanced, with the bus depot administration building already complete and the train depot offices and maintenance workshops targeted for completion within the next few months. The welding of rail track into 216 m long lengths has started at the temporary flash-butt-welding yard that has been set up adjacent to the train depot 

To subscribe to Engineering News's print magazine email subscriptions@creamermedia.co.za or buy now.