Upvote:8
According to Transport NSW, the line is disrupted between Katoomba and Springwood, so if you want to go to Bathurst, you should be able to board at Katoomba and take a train more-or-less as usual. If you wish to go towards Sydney, you will indeed have to board the rail replacement bus in order to meet the train at Springwood.
Needless to say, the situation is quite dynamic and you should recheck the journey planner as close to your expected departure as possible in case of any late changes.