[PRCo] Re: O-B Type G Double Curve Hangers

[Edward H. Lybarger]

Trolley wire in Pittsburgh was not that heavy, but it was as big as a dime's
diameter in Philadelphia.

-----Original Message-----
From: pittsburgh-railways-bounce at lists.dementia.org
[mailto:pittsburgh-railways-bounce at lists.dementia.org]On Behalf Of
robert simpson
Sent: Tuesday, September 11, 2007 7:19 PM
To: pittsburgh-railways at dementia.org
Subject: [PRCo] Re: O-B Type G Double Curve Hangers


Jim;

  I had no idea the trolley wires were as big as a dime in diameter!

  I also remember seeing very heavy cables running immediately beside the
PRCo tracks which I assume carried the bulk of the electrical supply.  Any
idea how big these cables were in diameter?

  Robert Simpson

Jim Holland <PRCoPCC at P-R-Co.com> wrote:
  Shown are the double curve hangers, one with wood strain insulator.
These are Self-Insulating with the cone on top part of the insulation
which fits into a hold in the hanger. Screw / Bolt in center of
insulated cone accepts *_Ear_* which is Hammered onto the Round
overhead. PRCo used Armors which wrapped around the wire from the
underside to protect the ear itself; this was done on Many Hangers but
not these two. Armors were also used leading into and out of frogs
because the wheel is at a considerable angle to the contact wire which
causes much more wear. Armors had to be hammered into place and took
Real Brute Force so to do~!~!
.
Our dimes are mostly copper today and a reasonable representation of the
contact wire cross section. Imagine stretching out a roll of dimes
100-feet long -- tremendous weight -- 1,000 to 1,500 pounds linear
tension is used to keep it taut. This is then mounted in the hangers
which have to hold the wire under all this tension As Well As be able to
withstand an *_Errant_* pole -- one which has left the
overhead~!~! With 32-pounds pressure of the trolley wheel against
the overhead with overhead 18' above the track, the pressure further
down the pole rises exponentially and an *_Errant_* pole will strike
spans and hangers at least 1/3rd the way down the pole.
.
While the hangers are self-insulating, current can *_Leak_* in some
fashion so that spans can carry some current. It is not uncommon,
and may be code, that two insulators are often used in a span - one here
near the contact wire and another near the line pole.
.
.
--
*Jim Holland*
Studying *Pittsburgh Railways Company*

....................From 1930 -- 1950

*Pennsylvania Trolley Museum (PTM)*

http://www.pa-trolley.org/

*N.M.R.A.*

http://www.nmra.org/



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