[PRCo] Re: Wheels__&__Shoes

[Boris Cefer]

This is an example of grooved trolley wire.
Does anybody have pictures of those old overhead insulators, frogs etc.?
Boris

----- Original Message -----
From: "Fred Schneider" <fschnei at supernet.com>
To: <pittsburgh-railways at dementia.org>
Sent: Wednesday, April 28, 2004 2:54 AM
Subject: [PRCo] Re: Wheels__&__Shoes


> Why did it take so long.  Wheels were reasonably suitable on a trolley
wire with
> a completely round cross-section that is held up by an ear that wraps
around the
> wire.  But those ears cause problems with anything that slides over it ...
the
> shoe wants to take chunks out of the ear and vice versa.
>
> The ideal solution was a pantograph.  But it requires a firm and properly
> aligned roadbed or the car will rock and ultimately the pan will catch
somewhere
> and tear down wires.  And it also wants a figure "8" cross section (or
grooved
> as Ken called it) wire which is clamped from the side ... the bottom
surface is
> perfectly smooth.  When trolley bus lines were installed, this type of
wire was
> installed initially.  But trolley lines had mostly "O" cross section wire
with
> ears wrapped around it, and it costs money to tear it all down and start
over.
> In a business that lost money over its entire life, you just didn't add to
the
> loss by tearing down wire just so you could hang up new wire.
>
> So why did PAT and Red Arrow wait until the 1980s to hang new wire?
Because by
> then it was done with Federal and State grant monies and not out of the
> farebox.  It doesn't even show in the operating expenses.   Why didn't
> Pittsburgh at least change to shoes earlier?  Probably no good reason to
spend
> the money.  Speeds were not high. Rolling stock wasn't heavy and power
robbing.
> And there was no joint operation with trolley coaches (both using the
positive
> wire).   Charles Shauck is dead, so is Karl Hittle, and R. Tighe so I
can't ask
> the question.  But we can observe two bankruptcies between in 23 years
between
> 1917 and 1950 and that may be all we need to answer the question.  I do
know
> that Charlie came out of every annual budget meeting with his requests
slashed
> deeply.
>
> I might add that pantographs were much more common in countries where
track
> maintenance is superior.  Russ Jackson was talking to one of the Kawasaki
people
> from Japan, a man who had observed that the PC (PRR and New Haven) strung
> contact wires directly over the track instead of staggering it back and
forth to
> spread wear across the pantograph shoe (common in most countries).  Russ
joked
> back that "We stagger the tracks."
> With staggered rail joints there can be a lot of sway in rolling stock,
and with
> undermaintained track the rocking is sufficient to allow a pantograph to
tear
> down the wire.  This generally isn't a problem on the other side of the
ponds,
> and therefore wire is staggered.  .
>
> Pantographs were
>
> ktjosephson at earthlink.net wrote:
>
> > Old WEPCO documents indicate that TMER&L believed that mixing shoes and
> > wheels was a problem because wheels tended to bounce and arc more often
> > shoes, causing the wire to peel. (See page 436, CERA Bulletin 112.) Cars
> > equipped with shoes would plane off the peelings,  supposedly weakening
the
> > wire. This was based on their own findings during the 1920s when rebuilt
> > interurban cars were equipped with shoes and run in mixed service with
> > wheel-equipped city cars on some stretches of street trackage. Greasing
the
> > wire seemed to help reduce wire wear.
> >
> > I wonder if TMER&L's conclusion was based on one individual's personal
> > belief, or if a superintendent needed an excuse to slip an all-shoe
fleet
> > proposal past the bean counters.
> >
> > I am certainly not an expert, but I would think the condition and type
of
> > wire (round or grooved), base spring tension on the cars, speed of
> > operation, road bed condition, etc. would affect the amount of bounce
the
> > collector would have as it rode along the wire. This is indicated in the
> > book as well as blaming starting with a heavy load from a dead stop with
> > such a small area of contact on the wire ("high current density") for
wire
> > wear.
> >
> > I do not know if mixing shoes with wheels really caused problems, or if
> > these problems are only evident on heavily traveled sections of line.
> >
> > Pittsburgh had lousy track for years and  used wheels long after most
other
> > North American operators went to shoes.
> >
> > Most operators found shoes to superior for all-around operation. As I
noted
> > above, maybe the Milwaukee system had a large stock pile of wheels and
> > wanted to justify a large scale conversion to shoes. Corporate leaders
are
> > more likely to let the worker bees make do with what's on hand unless
> > somebody can convince them that a major investment in change would be a
> > profitable benefit to the corporation.
> >
> > But I would like to know why Pittsburgh did stick with wheels for as
long as
> > it did. I know this was touched on in "Traction and Models" during the
mid
> > 1970s, but a definitive answer from PAT was never published in the
article.
> >
> > K.
>
>
>
>


-- Attached file removed by Ecartis and put at URL below --
-- Type: image/gif
-- Size: 3k (3256 bytes)
-- URL : http://lists.dementia.org/files/pittsburgh-railways/trolej.gif