If you follow a long transmission line you will see several pylon designs depending on terrain, river crossings, highways, and the like. Pylon design is a well

If you follow a long transmission line you will see several pylon designs depending on terrain, river crossings, highways, and the like. Pylon design is a well understood engineering problem with lots of software to over-engineer the designs. And yes they will need a reasonable inspection schedule as do all transmission lines.