Here's a picture I took behind my friend Paul's house out in western Davidson county near the Harpeth river. Everything you see was under water this past weekend. The picture quality isn't great, but you can see the large piles of gravel that used to make up the rail bed. Above that you can see the track hanging in mid-air.
Just to the left of this scene is the bridge where the railway crosses the Harpeth. It's obscured a good bit by trees and I didn't want to trudge through the mud to get a better look, but it looks like it's twisted and sagging towards the water. It's going to take some major repair work to get this route working again. This is the CSX line that runs between Nashville and Memphis and it's normally pretty busy.