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.

“Expect major delays on this line,” Sydney Trains boss Howard Collins tweeted on Monday.

He said the signal box had been badly damaged and would take at least three days to repair.

“This costs hundreds of thousands of dollars,” he said.

A motor vehicle has crashed through our boundary fence at Riverwood and damaged some of our signalling equipment.
As a result, some #AirportLine services may experience some delays.
Crews are on site working hard to keep services running safely and on time. pic.twitter.com/8S7xyFpNSQ

— T8 Sydney Trains (@T8SydneyTrains) February 10, 2019

The airport, Leppington and inner-west lines have all been affected. Authorities have urged commuters to allow at least 15 to 20 minutes extra to get to the airport.

NSW Transport Minister Andrew Constance said the line would not fully operational again until Thursday morning.

“This is a major incident on the network – there is no sugar-coating this,” he said.

“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.”

Mr Collins said the site of the signal box, which was installed in the mid-2000s, would be reviewed.

“It is a very rare event but we want to make sure we are offering maximum protection to our rail corridor,” he added.

-with agencies