Inertia on the power lines: Neandertal

We were on the Autobahn crossing the Neandertal. I was interested that there were concrete blocks hanging below the insulators. I have not seen that in the UK. I am guessing that there are cross winds. The inertia of the mass makes the wind less likely to move the lines. There do not seem to be the metal hammer end rockers on the wires that are used in the UK.