Trains are not moving through Nambucca Heads and XPT has been stopped once again.
On a very minor side matter, thread title, unless original poster has changed it after reading this post, is 'Northern Mainline', which is not the separate North Coast route through Taree, Nambucca Heads and Casino etc. The northern mainline is the Singleton Scone Werris Creek Tamworth Armidale route that used to go to Wallangarra. Then tedious costly break of gauge from standard to 1067mm gauge to Brisbane via Toowoomba.
The NSW northern mainline still carries very heavy tonnages including coal and grain etc from beyond Werris Creek, as well as passengers from as far as Armidale and Moree, with bus links beyond.
On the more important matter of the floods and its results on transport, certainly agree with David dm211060 who earlier reminded us in this thread that climate change means less reliable rain (as Flannery said), not that it won't rain at all. In fact, David wrote, warmer air is able to hold more water so more intense downpours causing flooding and risk of washaways are to be expected.