text: That geograph image is tagged 200m further south than this note, just south of where the power lines cross the road. So that could explain why I couldn’t find anything!
  
  I’ll leave the note open in case someone else can take a look.
  
  I did some reading and it seems this was a cable-pulled railway incline with a stationary engine at the top. I assume the threaded stone blocks were for cable guides then — they’re all aligned centrally in the track bed, and there aren’t anywhere near enough of them to act as sleepers.