The 160-metre, 885-ton tunnel-boring machine which has been shipped in from Germany, is now drilling into rock below the surface.
Work is ongoing at 45 sites along the multi-billion rand rapid rail link which will connect Johannesburg to Pretoria and the OR Tambo Airport.
The completed circuit will stretch for 80 kilometres of which 15 km will be underground.
Although the entire operation is not expected to be completed before 2011, project managers are confident that the main line from the centre of Johannesburg to the airport will be completed ahead of the 2010 World Cup.
