This is Dry Fork tunnel #1 (37.234365, -81.639281), about 470′ or so.  This is looking north from the trestle over the Rift-Berwind Road and Dry Fork River in West Virginia.  Bridge facing date is 1912, with a 1911 date on the trestle abutment.  Pending further research, I’d say the line here dates to the late 1800s, when the coal mines began to open up.  Our general theory with the lines in the area is that they blasted out the tunnels, leaving them unfinished if they were stable and ran the line over timber trestles until either the trains got heavier or the timber began to deteriorate, then they switched to the current configurations.  It’s a theory.