They knew about the rail closure/damage before doing the raising.
https://www.miragenews.com/update-2-queensland-rail-responds-to-cyclone-1164585/This article is from the 31st Jan and there are quite a few others.
"The Mount Isa line, however, is closed west of Julia Creek due to severe flooding at McKinnons Creek. While the water has subsided,
the track has been damaged and the railroad has been eroded by flowing water. With more rain expected in the region, it's possible the water levels could rise again."
