transportnsw.info says:
09:15 Central Station, Platform 9, Sydney

Central Coast & Newcastle Line 
Towards Newcastle via Strathfield

11:41 Broadmeadow Station, Platform 2, Broadmeadow
OPAL: $5.81
bookings.nswtrainlink.info says:
Tue 09:30 to Tue 11:45, 2h 15m Direct

$25.48
I suspect maybe both are true prices:
- the 9:15AM train can be paid with OPAL at $5.81
- the 9:30AM train costs $25.48 and can't be paid with OPAL.
The information is clear, only that the difference is too big. Is it true? I don't live in Sydney to tell.
Thanks:)
The $25.48 figure is for a booked interstate TrainLink (formerly CountryLink) service and the $5.81 figure is for the intercity service with no booked seats.