Telegraph lines lterally used the ground as their common. When railroads that had more than one telegraph wire, it often meant their poles were alos being used by Western Union or similiar company. These telegraph company lineman often had their own speeders for maintaining their lines.
On a line like RGS with fairly low volume, the railroad probably used their single line for both train movements and common carrier use. Did any of the RGS depots have a telegraph company sign hanging out front?
I worked for a shortline on Soo Line's Whitetail branch across ND into MT within sight of the Canadian border. It was supposed to have been one of the last lines to use telegraph (into the 1970s), and much of the single line still remained in 1991.