Delays of up to 20 minutes are expected to continue on the T8 Airport Line for three days after a car smashed into a signal box at Riverwood.
Sydney Trains chief executive Howard Collins and Transport Minister Andrew Constance said repairing the “vital” equipment would cost “hundreds of thousands of dollars”.
Mr Collins said trains were continuing to run slowly through the area, using manual signalling.
Passengers, particularly those travelling to the airport, should allow an extra 10 to 15 minutes when planning journeys, he said.
Mr Constance suggested passengers allow an extra 15 to 20 minutes.
Buses have been brought in to take people to intermediate stations along the line.
There are some knock-on effects for the T2 and T3 lines.
Mr Constance said it was likely to be Thursday morning before the T8 Line was fully operational.
“The challenge is not so much the lines into the city, but the lines back out to the suburbs,” he said.
“This is the equivalent of losing four sets of traffic lights on Elizabeth Street [City], that’s the type of impact.”
Mr Constance said his message to the driver responsible was “You have caused enormous grief to commuters for the next few days”.
“You should turn yourself into police.
“You left the scene. Obviously to have a reason for doing so, you might want to explain that to the hundreds of thousands of commuters who are going to be potentially impacted.”
Asked if terrorism was a possible cause, Mr Constance said it was a matter for the police to find and interview the driver.
Mr Constance said if anyone did have an accident on the rail corridor, they should notify authorities immediately “because you could actually derail a train and...there could be dire consequences”.
Mr Collins said Sydney Trains was “spending a lot of time and money” on upgrading security around rail installations.
“We continue to look at hundreds and hundreds of kilometres of track,” he said.
“I would like to build a wall all the way along the rail corridor, but it would be a bit tricky and impractical to do that because we have got to access that railway, as well.”
Mr Collins said there were about a dozen incidents each year of vehicles entering the rail corridor.
He said they were “doing work on key sites”, but he was “amazed at what motorists get up to, to be honest.”
A car has ploughed into a train signal box at Riverwood on Monday morning, causing delays to commuters on the train line.
Police say a white Honda Accord hit the box at the intersection of Romilly Street and Broadarrow Road, at 1.55am.
When officers from St George Police Area Command arrived to see what happened, the driver had left the scene.
The vehicle has been towed away and is being forensically examined.
Crews are on site and services in the area have been affected by the incident.
The crash is expected to cause delays for trains on the airport T8 line.
Passengers are urged to check via this link for updated information.
Inquiries are continuing into the identity of the driver, and anyone with information should call Kogarah Police Station.