[PRCo] Re: Cin

[Jim Holland]

Donald Galt wrote:
.
> Leaving aside the question of possibility, what would be the point of 
> this?

.
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My original response to this email has Not Shown Up Here.
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       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!~!~!~:::::::)
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http://lists.dementia.org/files/pittsburgh-railways/1166%20X%20Zoo%201950xxxx.jpg
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Why use the 3-wire system here?       Probably a number of reasons; just 
a few mentioned here.
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____A  "Total"  of Only 4 diverge frogs are
..................needed at the 4 circled overhead
..................intersections of the hand drawn map.
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________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!!!
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____Economy of Construction
____Economy of Maintenance
____Economy of Engineering
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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.
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Jim___Holland
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> Sadly, pictures of the loop that I have found don't show the overhead.
>
> Note:
> Anybody interested in Cincy ought to have a look at Jeffrey Jakucyk's 
> good and
> growing pages:
>
> http://homepage.mac.com/jjakucyk/Transit1/index.html#csr
>
> where you will find the "now" picture of the Zoo loop that Bill Robb 
> pointed
> us toward, along with many other things including an 
> painstakingly-crafted,
> very detailed interactive map of everything railway in and around 
> Cincinnati.
> Steam railroads, Cincinnati Street Railway, Green Line, inclines, 
> cable cars,
> interurbans - everything.
>
> Don G
>
>
>
>  
>


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