There were some good timelapse video and aerial shots of Hornsby changes on 7 news tonight. You can watch (low quality) here: https://twitter.com/twitter/statuses/951351973437063168
And below the new view from the north end of platform 2 - not sure how trains from Gosford/Berowra will get to platform 1.
While the tracks at Hornsby are mostly bidirectional, there are more signals in the primary direction.
Hence the above picture shows 2 Up main line signals on the Up Shore very close together, with no close together signals Up the Down Shore.