Extra train services are to be introduced on the Illawarra line in the late afternoon to address overcrowding.
The changes will also mean four services to Cronulla and Waterfall being faster.
Overcrowding on afternoon services, with a large number of school students travelling at this time, has become a growing problem, and it is likely Sydney Trains has had many complaints.
Transport Minister Andrew Constance said the timetable improvements would start on Monday October 17.
There will be three extra all stop trains between Bondi Junction and Hurstville in the PM peak, doubling the number departing Central between 3.15pm and 3.45pm.
The new services will enable four existing Cronulla and Waterfall bound services to stop at fewer stations.
This will address existing crowding on these services and reduce journey times for some customers by up to eight minutes.
Changes will also be made on the South Coast and Blue Mountains lines.
South Coast services will be improved by four express services stopping at Austinmer station.
Mr Constance said passenger numbers on the rail network continued to grow.
“While we get on with delivering major infrastructure projects like Sydney Metro, as well as building new suburban trains, we have to look at other ways we can use our existing network more effectively,” he said.
Mr Constance said data collected by Sydney Trains showed travel patterns were changing.
“There are now more day trippers, school children and those working flexible hours who want to leave the city earlier,” he said.
“A big part of these improvements is to cater for the changing needs of customers.
“We will continue to monitor the network to identify where we can deliver further improvements to current services.”
The introduction of extra trains on October 17 will result in the departure times of some existing services being changed.
Sydney Trains will distribute updated timetable booklets at stations along the Illawarra line.
Passengers are also advised to check times at: transportnsw.info and through online trip planning tools.