Sydney train commuters - including those headed for the airport - are set for at least three days of pain after a rogue driver destroyed a critical signal box.
Police are looking for the driver, who ploughed through a fence and into the equipment at Riverwood in the city's south about 2am on Monday before fleeing.
The incident caused delays along Sydney's airport train line and minor disruptions on others, with replacement buses called in to help.
Sydney Trains boss Howard Collins said the box would take at least three days to repair.
"This costs hundreds of thousands of dollars," he told reporters on Monday.
Authorities are urging commuters to allow at least 15-to-20 minutes extra to get to the airport.
The line isn't expected to be fully operational again until Thursday morning, NSW Transport Minister Andrew Constance said.
"This is a major incident on the network - there is no sugar-coating this," he told reporters.
"To the person that's responsible ... You should turn yourself into police. You left the scene, obviously you had a reason for doing so - you might want to explain that to the hundreds of thousands of commuters across Sydney that are going to be potentially impacted by this."