Communication and  Power Line Construction
by Robert Winkler

Reprinted from "INSULATORS - Crown Jewels of the Wire",, November 1970, page 3

I am very interested in past construction methods on communication and power lines and try to learn what I can about them.

The accompanying sketches were made from the Chicago South Shore and South Bend R. R. The first one shows the style of 34 SKV construction used by the utility company when the railroad was first in operation about 1910. This design was discontinued, as the circuits being so close together and the braces being of steel could, when wet, cause the current from one circuit to leak down the pin and burn through to the brace bolt. The current could then run along the steel brace to the other side, burn through to the pin and up to the other circuit, causing a short and damaging the equipment. 

About 1940 the design was changed to a straight circuit on either side using a three arm system and wood
braces. The lightning arrester system was also improved and grounded at  each pole. Other than the new pin-less insulators which are bolted directly to the  arms, this system has been the most popular to this date.

I would suppose early power companies elsewhere used the type of construction shown in the first sketch, but as of yet I have never heard of or seen any  others like it. In fact, on the whole line only three poles exist with the original  construction, and these have all been altered somewhat through the years.