It is reported that an overnight train derailment near Wollongong has thrown rail services south of Sydney into chaos until as least the weekend.

The freight train was fully laden with coal and heading to Port Kembla from Helensburgh when five wagons derailed at Clifton just after midnight. The incident left a jumble of twisted wagons that entirely blocked the track.

As a result buses are replacing CityRail trains between Thirroul and Waterfall.

RailCorp recovery crews are on site working to unload the coal from the wagons.

Concrete sleepers are also being removed from part of the track.

Despite the progress RailCorp says the track will not be fully restored until the weekend at the earliest.

(Sourced from www.abc.net.au)