Since undocumented (by me) railroad tunnels are rather thin on the ground right now, I’m going to soldier on by posting some rail overpass (auto underpass) features I’ve run across. This is on Cowan Gap Road in Southwest Virginia (36.61900, -82.68865). It’s dated 1907, so it’s probably original to the line (CSX). 125′ long (it is aslant the fill).