Geograph - photograph every grid square

The filled-in south entrance to Penmanshiel Tunnel in the foreground has become overgrown with dense scrub.
A train passes on the realigned East Coast Main Line in the background.
Penmanshiel Tunnel collapsed on the 17th March 1979 during engineering works to increase the size of the tunnel bore. Two workmen were entombed and remain in the tunnel. The collapse was sudden and unforeseen, resulting from a then unknown geological issue that had placed a section of the tunnel lining under significant stress. It is likely that the tunnel was already dangerously unstable before the engineering work started and it would have soon collapsed anyway; the consequences could have been much more serious.