Telegraph engineering : a manual for practicing telegraph engineers and engineering students (1922)
Hausmann, Erich, 1886- · New York : D. Van Nostrand Company · leaf 270
^ white cedar, chestnut,cypress, pine and redwood poles are principally used forthis purpose. These poles are from 20 to 80 feet in height,but those from 25 to 40 feet are the more usual. Theheight of poles to be used in a given locality is governedby several conditions, such as ordinances… … non-interference of the wires with the possible activities ofthe hre department, clearance at trolley and railway cross-ings, etc. The poles are from 5 to 8 inches in diameter atthe top, with an increase in diameter of about one inch inevery 10 feet toward the bottom. Poles are set from 5to 10 feet…
Telegraph
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