Dating in hounslow west
It has four 'dolls' because there were four possible lines a passing train could be routed onto.The higher the doll, the more important the route - the second line from the left was the through running line here.
Indeed almost the first subjects I pointed the EOS 20D at were signals at Worcester and Ledbury.
Each has its own style of spectacle glass casing too, and see how the rightmost doll is missing its finial!
The distant (lower, yellow) arms on the second and fourth dolls are of an unusual pattern that was only found at Newton Abbot - these are operated by motors (the black boxes) mounted immediately behind the arms themselves, a very rare arrangment, and again have a distinctive spectacle glass holder design. The shorter home arm on the very left leads to a lower-grade goods line, and the distant arm on the 3rd doll is fixed to indicate that trains must always proceed with caution when travelling by that route.
My grandfather had been a stationmaster in Malvern and our whole family understood trains and signals.
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!