The last surviving semaphore signals on Greater London passenger lines.
When I got a bit older, he explained how the signalling system works, and what actually happens inside those mysterious signal boxes - and I was hooked!
This is a lower-quadrant signal, as was standard on the GWR and the former Western Region of BR as it became - this means the arms move to point roughly 45 downwards to give a clear indication to the trains.
In doing so, this also brings the green spectacle lens in front of the corresponding oil lamp to give a visible indication at nighttime.
This site now includes photo pages of signals at: West of England centre where the GWR and LSWR main lines crossed one another.
I have included individual pages for Exeter West (above, right), Exeter Middle, Exeter Central, Cowley Bridge Junction and Exeter City Basin boxes.