L6 Estimation question A

Here are the electricity cables behind Wigton cemetery. If you enlarge this photograph, you'll be able to see the next pylon in the distance. Here are two questions to answer:
1. Why does the top wire have no insulator when the lower 6 wires hang from large insulators?
2. Estimate some quantities, look other quantities up and use the resistivity equation. Then calculate the TOTAL resistance between 2 pylons.