QUEENSLAND Rail has launched an urgent inquiry to find out why Brisbane's inner-city train lines have been cut by rising floodwaters three times in three months by heavy rain since November.
Sources say Queensland Rail is treating the issue extremely seriously because until recently train lines at Central Station, Fortitude Valley and Bowen Hills have not previously been cut by heavy rain.
There are suggestions that the 2011 floods may have changed drainage flows, though this is not confirmed, nor substantiated.
Train lines at inner-city train stations were cut on November 19 and 27 in 2014, and the past weekend.
Hundreds of commuters were stranded, with dozens walking home in the rain.
WATCH: Floodwaters inundate train tracks at Brisbane's Fortitude Valley station on November 27, 2014