Derailed acid train still off limits

It could be days before a derailed freight train which spilled tens of thousands of litres of sulfuric acid in northwest Queensland can be properly assessed.

All of the train's 26 carriages overturned at the Quarrells site, 20km east of Julia Creek, on Sunday.

Police say it was carrying 819,000 litres of the highly corrosive acid of which 31,500 litres leaked from one carriage.

Heavy rain and muddy ground have hampered efforts to reach the train, roughly 100 metres from the nearest road.

Queensland Rail said staff had not been able to access the site with a police exclusion zone of two kilometres not expected to be lifted until at least Thursday.

A spokeswoman said it was too early to say how long the clean-up would take but police have said it could be weeks.

The Flinders Highway between Julia Creek and Richmond as well as train lines in the area were still closed on Tuesday evening.