Many older main-route telegraph lines like this one having shorter crossarms with four or six insulators were rebuilt especially here in the northeast during 1910-1920 or so. The new lines were constructed with fresh poles (often cedar) with ten-pin crossarms, practically always with several arms per pole that allowed many more circuits. Western Union favored double petticoat insulators with such rebuilds, using zillions of B-beehives, Hemingray-40s and 42s, etc. Very frequently hard drawn copper wire replaced any iron wire that was still in use. Copper wire offered much better electrical conductivity and was stronger.

Photo credit: Shorpy.