[PRCo] Re: Bent Pole

[fwschneider at comcast.net]

Fred's best guess is that if you continually stress the trolley pole beyond the yield stress point, it will bend.   You need to understand that poles are not a solid piece of pipe of a single diameter but a tapered pipe made up of several pipes of different diameters.   The pole gradually becomes smaller and weaker as you progress from the base outward to the harp.   Dewiring it and slamming it agains span wires, the roof of a subway tunnel, bridge roofs, bracket arms, and other hindrances to its upward movement will cause it to bend.    Pulling power through a dewired pole arcing along overhead will heat it and weaken it too ... I remember watching one turn from black to orange when a motorman stupidly pulled power at Warrington and Beltzhoover while it was dewired and bouncing through the special work.   (I later saw that motorman very humbled in front of a supervisor on the porch at the Tunnel office.)   



By the way, I've about to meet Ken Josephson, Traci, and Karla for a drive down to Hoover Dam.  (I'll try to get the stupid cops to arrest me for taking pichurs.)   Have already ridden Phoenix, San Diego, seen the construction projects in LA, looked at organ pipe cactus, Death Valley, all sorts of great desert flowers, Canyon de Chelly ... great vacation.   Might even find a way to throw in Big Bend and Brownsville TX on the way home.   




----- Original Message ----- 
From: "BobDietrich" <bob.dietrich1 at verizon.net> 
To: pittsburgh-railways at dementia.org 
Sent: Friday, March 27, 2009 3:32:37 PM GMT -08:00 US/Canada Pacific 
Subject: [PRCo] Re: Bent Pole 

Here is a dumb guess! Â The spring tension on trolley poles often causes the 
poles to bow. Â Could it be that this is simply bowing of the pole, it would 
bow more in the center than toward the ends. Â Or could it be weakened there 
from so much bowing and appears to be starting to bend? 

OR could the retriever yanked it down so hard a couple of times that it 
bent? 

OK Fred & Ed, take your shots, I'm only making guesses????? 

Bob 


> ----- Original Message ---- 
> From: Ken and Tracie <ktjosephson at embarqmail.com> 
> To: pittsburgh-railways at dementia.org 
> Sent: Wednesday, March 25, 2009 9:18:38 PM 
> Subject: [PRCo] Bent Pole 
> 
> I have a couple dozen shots of Pittsburgh cars with bent poles. 
> Here's a shot of car 1702 with one. I wonder what happened? 
> Not likely to for an interurban using the Dormont wye. 
> Perhaps back-poling in the shop or yards? 
> K. 
> 
> 
http://lists.dementia.org/files/pittsburgh-railways/pat1702.jpg 



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