This looks like a pretty old 6-pin telegraph line, perhaps built in the 1890s and probably outfitted with crown-embossed CD 145 Brookfields (aka CREBs). Owing to the rather decrepid appearance of this line and the fact it probably had iron wire lines going back (goodness knows how old...) lines like this were thoroughly rebuilt starting around 1910. The CD 145 and CD 151 (double-petticoat) insulators were "recycled" and thus resused as well as usable other line hardware such as pins, crossarms and braces. With Western Union, only double-petticoat insulators were installed on their upgraded lines. Beyond this, cedar poles were the replacements...at least here in the Northeast. Boy...did a lot of them last a long time!! Crossarm construction was of the 10-pin design and the line wire made of hard-drawn solid copper. Pins had metal cores with wooden cobs. These were introduced by the mid 1890s and I am sure a lot of them were re-used during Western Union (and other telegraph company) line-rebuilding projects of the early 20th century. Many of these telegraph lines remained in service through many decades, well into the 1970s.