I presume about here.
Australia, and NSW in Particular, often has 4 track mainlines , in places where I thought the number of trains did not warrant it. in Fact , a quick scan of the tracks in the above link, I can't see a train on any of the tracks, though don't know what time of day it is . Possibly it is to allow passenger trains to pass long coal trains.
I'm not really a steam fan , so can't answer your other questions.
Moderator worldwide railfan
, Rail travel & trip reports
The only train trips I regret are the ones I didn't take.