Eight trains an hour will leave Sydney Olympic Park between 6pm and 8pm after Sunday's NRL preliminary final.
The services will connect departing supporters with Central and Strathfield, where they can continue towards Newcastle and the Hunter.
The Newcastle Knights will meet the Penrith Panthers at Accor Stadium from 4pm, with an NRL Grand Final place at stake.
To assist the expected travelling crowd, Sydney Trains is adding two Newcastle-bound services before the match and two returning services afterwards.
The extra Newcastle Interchange departures are scheduled for 12:01pm and 12:56pm, reaching Strathfield at 2:38pm and 3:16pm respectively.
At Strathfield, supporters can transfer to Sydney Olympic Park trains, which will operate every 10 minutes before kick-off.
Fans are encouraged to check the Transport for NSW website for the latest timetable details.
They can also wear their team colours as Knights supporters travel south to create a red-and-blue crowd at Accor Stadium.