Thanks for the information. I didn't think about WU lines.
You reference a "return line," and that four wires indicate two "lines." These lines are earth-return, so each wire on an insulator is a separate communications channel (not two wires per channel, which would double the material cost). If your "return line" goes back up on the pole (instead of to ground), it's probably the second wire going into the station.
My terminology is probably poor. By return line, I mean the return from the set in the station, if the set is in series on the line. I assume all sets were in series on a given line, so the line had to go into the station and back out again to continue to the next station, or wherever.
The picture of Ophir depot shows power lines running into the Lizard Head end of the station. The telegraph wires ran thru the supports for the ore bin and, I think went into the baggage end of the station. The four wires on the pole beside the trestle are the ones that come up the low line. I believe they are actually two lines, again since I assume it is a series hookup, they both go into the station and back out again. Ophir had an order board, but by 1943 was listed as a telegraphone station, while Placerville was a telegraph station.
Peak and Lizard Head were telegraphone stations too and there was no order board at either location. I have one dispatcher's sheet showing time at Lizard Head, so the train must have contacted the DS from there. The more I find out about this the more I find out I don't know.