Update 06/02/15...Actually the AT&T line stood a few blocks away (not in view). Shown is a Southern Pacific RR comms line. There certainly was some interesting openwire in that area! Thanks Bart.

Original caption...I believe this openwire route was a very significant Bell System long distance telephone and telecommunications connection from the west coast (from San Francisco) to points eastward, including Chicago and other cities in eastern United States. In addition to telephone conversations, other media such as music, teletype and radio broadcasts were sent along it.