N2EY wrote:

Yes, but there were several reasons for the normally-energized series
line systems.

Another thing is that telegraph "lines" might indeed be a single wire..
Using the Ground as the "Return" for the loop

This was often done both for telegraph and for mains electrical at one
time due to a shortage of metal for the wires... This is very likely why
house systems have a ground bonded to the neutral at the service
entrance AND AT THE POLE.. At one time they simply forgot to use a neutral.

Plus I"ve seen several "Loop" systems today where a single wire is
looped from the "Central office" out to each "node" or station and all
the way back.. One such was made by Phillips back in 1980.. I used to be
one of the operators (This was a telephone system) the finished product,
I used to joke, had one part that NEVER FAILED... That was a reset
button... The original failed and the replacement came from Radio Shack.