Color of Wire on Pole Line

[NW Mailing List]

Comrade Mishko Rectorovko doth ye ask about the color of wire on N&W pole line.  Only time I ever had such a question !

Okay, Mike, I am not going to give you a straight answer; I shall tell you the history and options and send you some photos, let you choose for yourself. Buckle your seat belt, here we go...

1. The earliest line wire was iron. Matter of fact, it was "three ply" (meaning three strands of wire twisted or woven together) used between Baltimore and Washington in 1844, along the B&O. One early record says the strands were 16 gauge, but it is unclear whether the writer was using the british or the American Wire Gauge.  At any rate, it was a technological failure: It was a sponge for water and rusted away very quickly.

2. The next year, late 1845, they went to single strand of Copper wire, 16 gauge as I recall. This was on the telegraph line along the Harrisburg Portsmouth Mount Joy & Lancaster RR, which ran from Lancaster to Harrisburg, about 35 miles. these guys used buckets of tar and tarred their wire, in the attempt to precent corrosion ! But it, too, was a complete failure because they did not yet understand the annealing of metals and it was constantly breaking.

3. As technology developed, pole line construction and the use of wire spread like topsy, the price of Copper became prohibitive, and Iron wire was ubiquitous on American pole line for several decades despite its drawbacks.

Copper was weak, Iron wire was strong. But Iron offered 900% greater resistance to the flow of electrical current than Copper. (Those are numbers quoted from the statistics of that day: Both Copper and Iron wire had significant metallurgical impurities, which greatly increased the electrical resistance.) Since there were no dynamos back then, all electricity had to be generated chemically, with acid + Zinc + Copper (or in some cases Platinum,) and each cell of battery produced about 1.2 volts. If you needed 160 volts for the operation of a line, guess how many cells of battery you would have to make? Yes, 134 cells.

Iron wire made for stronger pole line construction more able to withstand storms, but when poles did fall during storms or train wrecks, the wires usually fractured. Copper wire produced a pole line less able to stand up to storms, but when the poles fell over the wires generally stretched instead of breaking. So each metal had its advantages and disadvantages.

Over time, the increasing purity of the metals, coupled with annealing, produced stronger wires with far less resistance.

The quantum leap ahead came in the 1870s with the introduction of something called Compound Wire, which was Iron wire wrapped with strips of thin Copper. Iron gave the strength, but the current followed the Copper exterior which had a much lower electrical resistance. The problem with Compound Wire was that the Copper strips were imperfectly bonded to the Iron core, and came loose after several years of service, leading to the same old problems of high electrical resistance and rusting Iron wire. One article says that in Pittsburgh, line wire often did not last more than 8 years.

At some point in the 1880s there was invented a process for electroplating (if that is the right word) the Copper jacket on a steel wire, and the resulting product came to be marketed under the names Copper-Clad and Copperweld.   At last they had produced a product with the strength of Iron and conducting capabilities approaching that of Cupper.  This was what the N&W and other railroads were using at the end of pole line. (I think both products are still made.)

4. NOW AS TO COLOR... the issue is, to what color do these kinds of wires oxidize whenn they weather? And I will answer this by showing you photographs.

The first attached photo shows a piece of early Iron wire which I removed from pole line on the Erie RR Old Main Line west of Hornell. It is badly rusted and probably 50% of the Iron has oxidized away. The wire was so hard I could not cut it with a big set of lineman's pliers, but was so eaten away by corrosion that if flexed once or twice, it broke easily. (I have a chunk of this carrying an operating Telegraph circuit in my basement and, in order to solder a connecting wire at each end, I had to file away the oxidization until I found enough clean metal to hold a solder joint.)

The second attached photograph shows two pieces of standard railroad No. 9 Copper wire (not Copperclad or Copper-Weld, but real Copper wire.) These two pieces of wire no doubt looked identical when strung, but one has odixized to a green color, and the other to a brown color. Why is one green and the other brown?

The top wire in the photograph (green) I removed from the PRR's M&CC Branch, which was downwind from the American Viscose Plant in Lewistown, Pa. Translation: it got blasted for decades by air laden with Suphuric Acid.

The bottom wire in the photograph (brown) was removed from the desert east of Wells, Nevada. And we know that the old Central Pacific RR in that area was re-routed in 1902, so this wire laid in the alkali desert from 1902 until pilled out of the sand in 2012.

I sent this photograph to a chemist, and his response verified my suspicions. One wire had oxidized green due to the acid, the other had oxidized brown due to the alkali desert. (Someone will no doubt take umbrage with my wording here, but that is okay.)

I also have a roll of Copper-Weld and just looked at it. The color is an ugly, flat, dull gray-green resembling flat-surface green latex paint which is old, dirty and ugly. If you want, I can take a photo of in the sunlight.

Since you are a good customer, I will also throw in photos of Iron wire splices and Copper wire Western Union splices from the Transcontinental Railroad in Nevada, and a very sloppily done Western Union wire splice on the PRR done using an early crimp-sleeve, probably dating from the 1890s.

So, the choice is yours: I have supplied you with the history and some "color swatches." (Check the file names for details.) Happy painting ! HA !

   -- abram burnett
Decriminalize Turnips !
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