Melbourne Central and Flagstaff stations were evacuated late on Thursday evening after extensive flooding damaged several platforms.
A man and woman had earlier got into a stairwell connecting platforms at Melbourne Central before damaging a water pipe and fire sprinkler, police said, releasing security footage of the man and woman sought in the investigation.
The flooding triggered an automated evacuation in the two stations, causing significant train delays.
While the flooding was initially believed to have stemmed from an act of vandalism, Transport Infrastructure Minister Danny Pearson said vision had proved otherwise.
“I’ve been advised that Metro (Trains) have reviewed the CCTV footage and it would appear that an amorous couple in a stairwell dislodged the sprinkler,” he said.
“Perhaps a stairwell may not be an appropriate place to find yourself in after dinner.”
– AAP