Those wires we call drop wires. Back in those days they were solid copper wire which were tightened with a ratchet. When I started on British Telecom, as it was back then, there were still customers served by "open wires" from poles to houses.
There is still the odd pole with cross arms on it but they are virtually gone now.
Those little pots on those poles are ceramic.
Those were the days!!!
Would you need to pack a pair of brown trousers for climbing those things, I wonder?
Also, did anyone ever fall of them? Can imagine some sneaky nut working out the exact height to fall and survive for a compo job if no win no fee had been a thing back then?