[PRCo] O-B Type G Double Curve Hangers

[Jim Holland]

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/



-- Attached file removed by Ecartis and put at URL below --
-- Type: image/jpeg
-- Size: 82k (84684 bytes)
-- URL : http://lists.dementia.org/files/pittsburgh-railways/Hanger%20curve%2042%20Brookside%20196xxxxx.jpg


-- Attached file removed by Ecartis and put at URL below --
-- Type: image/jpeg
-- Size: 70k (72556 bytes)
-- URL : http://lists.dementia.org/files/pittsburgh-railways/Hanger%20Curve%20Insulator%2042%20Brookside%20196xxxxx.jpg.jpg