That's fine Trainplanner;
I have been out of the rail industry for nearly 9 years now. (redundancy).
At my previous employer at Pacific National (and NSW FreightCorp)
we used to a have log in web site (internal intra net)
to view the working timetables.
After I left P/N, I logged (joined) into ARTC website to view the timetables etc
I did let it lapse a few years ago and have not been available to view it since then.
Once You "joined up" and logged into their site;
I am pretty sure they also had the timetables of the freight trains.
(even though, laugh! they never really run to those schedules !! )
By looking at the prefix and number of the train
you can assume the turnaround times.
So; if no one else could help You with your question in the rail industry or on Railpage Forums
this could be one way of finding out.
PS: Most long freight trains when needing a "FULL" brake/train examination are approx. 60-90 minutes.
It used to be 40 minutes at Botany Yard for a 900 metre length freight train.
(ie the length of the Botany Sidings unless the train examination was done on the main line)
but most intermodal freight trains can be upto 1500 metres in length, out of Chullora. (I think)
Loco prep and refuel could be around the same 1-2 hours. (depending on amount of locomotives)
Again though: I have been out of the rail industry for nearly 9 years and things may have changed.
Just before I left the rail industry, even the "full" train examinations certificates guidelines was modified
to let trains run back and forward with the same original certificate if the train consist was not altered.
Meaning a "train driver or assistant can do a modified certificate of examination and "roll by" at arrival & or departure.