Aah.. thank you for the information.. I have been looking for a good iPhone Photo app :)
Ok, this is quite a Sherlock Holmes challenge :D. No wonder your profile says "alter ego of Australian crime writer ". You love this kind of mysteries! :)
So, I see one comment mentioned that the photo shows platform 25 but you end your travel on platform 24.
Then I noticed that Kiama has no T number (T being Terminal?).
Also, it shows Platform 3 and Platform 2 while the other 2 has T4 and Platform 1. Ok, I have no idea how the signage works for Sydney's train stations, so this might not be it :D