My color ID program (Colorblind Assistant) calls this “rosy brown”. I think it’s pink..ish.
It’s located just down from the coal house in Middlesboro KY.
This 600′ or so curved tunnel is in Bell County KY between Pineville and Middlesboro (36.713553, -83.671519 off Patterson Branch Road). The unfinished portal is on the south.
The line appears to be abandoned. I saw a few rail dates in the 1920s and the faceup on the north portal has a 1944 date. However, I think the tunnel is much older than that, since the L&N ran a line in this area sometime after 1890 (as far as I can tell…corrections happily accepted).
I walked through the tunnel and saw only one rockfall area.
Note: walking through a tunnel is not a good idea.