Construction has begun on a temporary track around the site of a derailed train in Queensland's northwest.
The train was carrying more than 800,000 litres of sulfuric acid, of which about 31,500 litres spilled, when all 26 of its wagons overturned near Julia Creek on December 27, closing the Mount Isa line.
The closure has created a backlog of freight services and forced the Inlander service to be replaced by buses.
Wet conditions have hampered the recovery but construction of the 800-metre bypass began overnight on Thursday.
Queensland Rail's Michael Mitchell said more than 50 staff would work around the clock building the track in a bid to re-open the line as soon as possible.
"Conditions permitting, we expect construction and certification of the rail deviation to be complete middle of next week," he said.
The sulfuric acid spillage has also caused environmental headaches.
Water testing around the crash site came back positive for the toxic chemical at Horse Creek, a small slow-flowing waterway, prompting authorities to neutralise the acid.
It was initially estimated that 31,500 litres had spilled from one wagon, but this week it became apparent that a second wagon may also have a minor leak.
Queensland Rail has appointed a consulting company to undertake an environmental monitoring program and to provide expert advice about any environmental impacts.