Trains are once again able to travel between Toowoomba in southern Queensland and Brisbane.
Queensland Rail says last month's wet weather caused a land slip on the Toowoomba range railway, washing away about 9,000 cubic metres of soil.
Queensland Rail spokesman Graham Brown says several sections of the line were damaged in a similar way to the 2011 flood.
"Earlier on we thought maybe it would be more like four or five weeks' work," he said.
"But once we got into it and did some planning and got the geotechnical investigation done, we forecast that Thiess would finish by the Saturday.
"Then there was some railway works to do over the weekend to reinstate the rail line etc and basically we were back on timetable."