[PRCo] Re: Cin

[Boris Cefer]

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.
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.

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%201950xxx
x.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
>
> -- Attached file removed by Ecartis and put at URL below --
> -- Type: image/jpeg
> -- Size: 57k (58811 bytes)
> -- URL :
http://lists.dementia.org/files/pittsburgh-railways/03-Map%2049-78%20hand%20
0072.jpg