I have not seen anything official on rail damage in NC yet, but based on photos I have seen from the NC mountains I would bet:
- NS from Newport TN to Asheville along the French Broad is likely to be completely gone
- NS from Asheville (and the Biltmore yard) to Black Mountain has been underwater, but the Swananoa is fairly low volume so the track is perhaps intact.
Given the light traffic West of Asheville, I would be very surprised to see NS rebuild any of it. NCDOT may step in East of Asheville given their passenger rail interest (which is misplaced in the eyes of this foamer, the run will never be fast enough to serve anyone but rail-positive tourists)
- CSX from Marion to Erwin has undoubtedly seen multiple washouts. I have not heard anything from the Spruce Pine area but both Erwin and Boone (not on the line but nearby) have both suffered substantial damage (the hospital in Erwin was underwater)
- The mostly lowland ex-Clinchfield from Bostic towards Spartanburg has likely seen a substantial amount of bridge damage (it is possible the Lake Lure dam has failed and flooding along that slope has been severe regardless of the status of the dam -- the village of Chimney Rock appears to have been wiped away by the water)
The common theme to all four of these segments is they were all either in, or very near, mothball status. While all of these areas have seen floods like this before, current traffic levels might be the thing to bring an end to railroading in the NC Blue Ridge. The storm has also undoubtedly increased the degree of difficulty for Salisbury-Asheville passenger service.
Based on other damage reports I doubt any rail east of Morgantown has seen any significant damage.
As to alternate routes, I-40 has washed out at the TN-NC stateline (it is normally closed due to rock slides every couple of years, this is the first flood-related closure in my memory). I-40 in Asheville (near the 74 interchange) was a river earlier today as well.