Cowan Gap tunnel January 1, 2014January 1, 2014Bob Lawrence Well, it’s a tunnel, since it’s on Cowan Gap Tunnel Road (Hwy. 636) in southwest Virginia. This railroad (CSX) underpass, from 1907, is about 125′ long and runs aslant under the railroad. This is at 36.61900, -82.68865. Share this:TwitterFacebookLike this:Like Loading... Related