In the US, all power distribution is three phase and therefore all major power towers have three major conductors, and two (sometimes only one) small minor conductors, which are a grounds that are usually the top two cornner wires, which are for lightning protection. In power (sub) stations everything is in groups of three's (like transformers and capacitors banks).
Now days, because of the Internet, there is a additional small line (on major towers) that is strung in the middle and below the other conductors - it is a long line fiber optic bundle. I am not sure if the fiber bundle is used by the Internet in general or there for the power company use only.
None of this should effect your great models - it's just FYI
