[PRCo] Re: Cin

[Jim Holland]

Believe we have discussed this before  --  reversing polarity in dual 
trolleypole systems  (TrolleyCar and TrolleyCoach)  doesn't affect the 
motors  --  we still have situations on the TrolleyBuses here in SF 
where overhead polarity will change for a short stretch in complicated 
intersections.
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Actually, I am going to guess that the center wire In This Situation in 
Cincinnati was the ground and the outside wires were hot.       Look at 
the overhead Just behind the car in this photo and you shall notice a 
contactor on each of the two outside wires:
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http://lists.dementia.org/files/pittsburgh-railways/1166%20X%20Zoo%201950xxxx.jpg
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Putting this together with the adjacent in street trackage which has 
triple overhead and the apparent split in two different directions in 
the distance suggesting At Least 2 different routes using this loop, it 
seems that the zoo loop itself contains two separate track loops.       
The above mentioned contactors set the switch automatically for either 
of the two loops so each line can layover without blocking the 
other.       They share the same track to leave the loop but split into 
two different directions up the street  --  the switch can be thrown 
automatically there as well.
.
The contactors in the overhead just complete the circuit to throw the 
switch WithOut Motorman Interaction, one to the left and the other 
straight, and putting this in the Positive Power feed makes the most 
sense.       The positive power feed could also go directly to the 
switch motor with the poles completing the circuit through the contactor 
and ground wire, but that would be an overly fancy way of grounding the 
motor when it could be done more simply in other ways.
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Jim___Holland
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Fred Schneider wrote:
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> No one has questioned it yet but before they do: I would assume that 
> the middle wire is the positive wire and the two outside wires are 
> negative grounds but it doesn't matter. Unlike model railroad motors 
> with permanent magnets for a field, the trolley cars and trolley buses 
> used series wound motors. If you reversed the polarity of the field, 
> you also reversed the polarity of the armature simultaneously and the 
> car continued to run in the same direction.    So reversing which wire 
> was positive and which was negative had absolutely no affect.
>
> To reverse the car you have to change the direction of the motor field 
> connections versus those of the motor armature connections and that 
> reversal is done on the car. The old Lionel toy locomotives also had 
> series wound motors ... remember the little reverse switch that came 
> out the top of the boiler?
>
> Jim Holland wrote:
>
>> Here's a couple interesting shots of Cincinnati:::::::
>> .
>> 1166 appears to be on a short stretch of single track -- ON prw ON 
>> the Sidewalk(!!!) -- with 3-wire overhead, one wire shared in common 
>> in both directions. Note the overhead in the distance how it 
>> separates into w sets of double overhead and it is doing the same 
>> above the front end of the car.
>> .
>> The second photo with 1165 confirms that there is a second track at 
>> this location again with triple overhead, a set of which turns left 
>> across the overhead that goes over the sidewalk! Would like to know 
>> more about the track layout here and if this is really near the Zoo 
>> for which there may be several layover tracks!!
>> .
>> .
>> http://lists.dementia.org/files/pittsburgh-railways/1166%20X%20Zoo%201950xxxx.jpg
>>
>> http://lists.dementia.org/files/pittsburgh-railways/1165%20Lockland%20&%20follower%201950xxxx.jpg
>

>> On Jan 15, 2007, at 11:00 AM, Bill Robb wrote:
>>
>> Here's a photo of the Zoo loop:
>>
>> http://homepage.mac.com/jjakucyk/Transit1/loops/pages/page_4.html
>>
>> Cincinnati streetcar info:
>>
>> http://homepage.mac.com/jjakucyk/Transit1/index.html#csr
>>
>> Cincinnati Transit Historical Assn.
>>
>> http://www.ctha.org/index.shtml
>