I suppose this went out of passenger service in the 50s, around the end of the steam era.
This is Brush Creek (thanks, Jon Hirst!) tunnel between Green Mountain and Red Hill NC, on Green Mountain Road…all west of Bakersville. Funny thing about tunnels: you can be more or less in the center of a short tunnel where you can see bright daylight from each portal, but where you’re standing, it’s pitch black.