This is a CSX Clevinger Branch Coal Run subdivision (read about it here) tunnel near Clevinger Branch Road (3227), about 3 miles NE of Coal Run Village in Pike County KY.  Coordinates (at center) are 37.5519, -82.5239.  It’s about 1,500′ long on an active line.
Inside the tunnel, the ties are concrete:

 

The ballast is covering the center of the ties.  I’ve seen flat (and cracked) concrete ties at the Indian Ridge tunnel in Johnson City, but none like these. Interesting.