[PRCo] Re: Cin

[Jim Holland]

FIRST____RESEND:::::::
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Boris Cefer wrote:
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> Your drawing is probably correct, but I feel a need to make a few 
> comments.
>
> This layout was built before the PCCs came in service and the old 
> streetcar equipment did not mind polarity change because it did not 
> have low voltage control circuits. They could build it with 2 wires 
> and much hardware or with 4 wires and practically no hardware, but 
> which wersion would be less expensive? This way they saved wire and 
> hangers.

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THIS___ is why I asked about the old Flyer TCs here in SF  --  thought 
there might be a similarity to the old time TrolleyCars and I Do 
understand the reason they would not be affected.
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Do Not Doubt your comments about low voltage circuitry on the PCCs and 
Polarity Reverse in the overhead    ----    just looking for an overall 
understanding with the Cincy system.
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With a Standard Single Pole TrolleyCar, Polarity Reverse is not a 
problem  --  positive is not placed in the rails.       So why would a 
standard single pole PCC be set up to accommodate polarity reverse In 
The Overhead?       It couldn't share overhead with a TC where polarity 
reverse took place because   I-F   that happened in the TC overhead the 
TrolleyCar TrolleyPole would be on a negative wire as are the wheels on 
the track  --  car would go dead!!!
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It is Very Plain from that photo of Cincy 1166 that insulators were Not 
used in the 3-wire overhead so polarity reverse was in effect 
here.       It would seem Most Logical that polarity reverse for the 
78-Outbound happened when it crossed the 49-Inbound; polarity reverse 
could return to normal for the outbound 78 where it crossed the 
49-loop.       Insulators would be needed at both these  Crossing  
Locations regardless and economy would dictate that this be the place to 
make the change.       78 inbound uses standard polarity configuration 
throughout this location, even the 3-wire section.
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Outbound 49 has standard polarity configuration through the 3-wire 
shared overhead outbound with the 78, goes into the loop, then when it 
crosses the outbound 78, the 49 experiences polarity reverse so it can 
share the 3-wire overhead with the inbound 78.       When the inbound 49 
crosses the outbound 78 the polarity configuration would return to 
normal.       Great economy here in using existing overhead to configure 
this and  Significantly  Reducing the amount of special work needed by 
the 3-wire system.
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Thus, Cincy PCCs were probably wired to accommodate polarity reverse but 
seriously doubt that Pittsburgh, Philly, Chicago, Detroit, San Fran etc. 
would be wired for overhead polarity reverse  --  need doesn't exist!!
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> PCCs would mind polarity change unless some provision in the equipment 
> was made (we need a schematic diagram to prove this) or it was simply 
> ignored by CSR that the PCC equipment would not work correctly.


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Agreed    ----    and as stated above, because of the photo of 1166 
which is totally devoid of insulators in this overhead, it is obvious 
that polarity reverse is in effect here.       The Only thing which 
would rule this out is   I-F    each route tripped a relay which set up  
PROPER  polarity for that particular route coming through, but it would 
have to be set up so that the other route could not activate a relay 
until the route already in the 3-wire section has cleared same!!!
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As you mention, this would not have been a problem for the Old Cincy 
Cars, Non-PCCs, so it seems most obvious that Polarity reverse is 
evident from the photos and the PCCs had to be modified to accommodate.
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I Am Sure you shall be able to find Schematics for the Cincy PCCs    
----    You  Possess  Super--Sleuth  abilities concerning  
PCCs!!!!!!!       We shall be waiting to hear from you!!!!!
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Jim___Holland
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> Further discussion is, in my opinion, wasted time because we do not 
> know all facts.
>
> B
>
> ----- Original Message -----
> From: "Jim Holland" <prcopcc at p-r-co.com>
> To: "- 1714 PRCo__WP__JTC (WP-Cleveland;__DCT) -"
> <pittsburgh-railways at dementia.org>; "- 1717 PRCo__WP__JTC
> (WP-Cleveland;__DCT) -" <pittsburgh-railways at dementia.org>
> Sent: Wednesday, January 17, 2007 11:15 AM
> Subject: [PRCo] Re: Cin
>
>> .
>> My original response to this email has Not Shown Up Here.
>> .
>> Found a General Map of Cin in my files, possibly made by the railway. 
>> A portion of that map is included as the first photo herein. This 
>> 3-wire overhead is shared by the 49 and 78 TrolleyCar lines and my 
>> previous conjectures about the advantages of the 3-wire over 2-wire 
>> overhead are borne out after reviewing the map. About center left on 
>> the map is the word ZOO in a box as well as 49 in a circle. Nothing 
>> is said about the 49 terminating here except the Name of the Route 
>> which is "Zoo_Eden_Park" and the map doesn't show a loop. Trace the 
>> 49 and you will note that the number is always enclosed in a circle 
>> (on many maps the indicator around a number showing the terminal will 
>> be different from that used to indicate the routing along the way.) 
>> From near downtown the 49 heads outbound on Sinton, Gilbert, 
>> McMillan, May, Oak, Reading, Melish, Burnet, and Finally Erkenbrecher 
>> due West where it Joins the 78 coming out on Vine. Thus the 3-wire 
>> portion both OUTbound & INbound is a short stretch on Vine, about 3 
>> or 4 car lengths each direction.
>> .
>> In the second enclosed photo I have drawn a crude map of this 
>> intersection of Vine and Erkenbrecher showing the Overhead with the 
>> 3-wires and the loop ---- while this "cannot_prove" that the 
>> contactors we see above & behind 1166 in the following URL are 
>> dedicated for setting the switch at the loop for each route 
>> regardless of what the operator does while passing through said 
>> contactors, it does very strongly suggest this As Well As strongly 
>> suggest that the outside wires are positive ('could' be negative but 
>> it would be a strange way to operate the switch -- feed it positive 
>> and return the ground through a contactor completed by the trolley 
>> collector!~!~!~:::::::)
>> .
>
http://lists.dementia.org/files/pittsburgh-railways/1166%20X%20Zoo%201950xxxx.jpg 


>> .
>> Why use the 3-wire system here? Probably a number of reasons; just a 
>> few mentioned here.
>> .
>> ____A "Total" of Only 4 diverge frogs are
>> ..................needed at the 4 circled overhead
>> ..................intersections of the hand drawn map.
>> .
>> ________Using a 2-wire system the following
>> ........................items would be needed:::::::
>> ________________8 diverge frogs
>> ________________4 crossing frogs
>> ________________8 insulators to prevent shorting
>> ....................................positive and negative wires!!!
>> .
>> ____Economy of Construction
>> ____Economy of Maintenance
>> ____Economy of Engineering
>> .
>> The last photo herein shows the typical 2-wire intersection with all 
>> the frogs and insulators which would have to be used at each circled 
>> location on the hand drawn map. This is a considerable amount of 
>> weight. Additionally, two wires terminate at the diverge frogs both 
>> trailing and leading so this puts extra strain on the overhead (about 
>> 1,500-pounds +++ linear tension On Each Wire to keep the overhead 
>> taut) so it would probably be necessary to run an extra span or two 
>> from these diverge frogs, lead and trail, to a line pole to balance 
>> this tension And that might require several extra line poles!!!
>> .
>> The electrical needs for the two turnouts -- one into the loop and 
>> the other where the inbound 49 and 78 separate at Vine and 
>> Erkenbrecher Inbound -- would be the same but require two contactors 
>> at each turnout with a 3-wire system as compared to one contactor at 
>> each turnout for a 2-wire system. The contactor used for the 3-wire 
>> setup is the simple contactor used to set Nachods where the wheel / 
>> shoe completes the circuit between the contactor and the overhead; 
>> normal switch contactor is a little more complicated and probably a 
>> little more expensive so there would be marginal extra cost using two 
>> extra but simpler contactors.
>> .
>> Fibers wear easily and can crack and fall out of insulators which 
>> almost guarantees a dewirement which can then 'possibly' cause damage 
>> to the overhead and or trolley pole and even pull a span loose or 
>> break one, or possibly break the overhead.
>> .
>> .
>> .
>> Jim___Holland
>>
>>
http://lists.dementia.org/files/pittsburgh-railways/03-Map%2049-78%20hand%200072.jpg