Hmmm, Bathurst has a lot of train stations as well as Parramatta, why not try try visiting the NSW city rail link website, you should be able to receive the timesheet and the travel length from there.
http://funadvice.com/r/3kt773pd15
The regular time, takes 35 min. to 45 min., but if the train will encounter such problem, I think, it will take an hour...