tomikawaTT
Inside a tunnel. The most extreme example I encountered had continuous guard rails from one tunnel portal (started about forty feet short of the bore) to the far end of a second tunnel. Both tunnels were long - and they were separated by a concrete arch bridge that spanned a gorge. [The tunnels and bridge are still there, but they haven't felt the weight of a train for half a century or more.]
This sounds quite interesting! I'd like to Google Earth it. Where is it?
