[PRCo] Re: Trolley question

[Schneider Fred]

To elaborate on Phil's comment, London England used to use swivel  
shoes with wheels on their tram cars, principally because their poles  
were not centered in the middle of the cars but off to the side and  
the harp had to allow the wheel to swivel from side to side to enable  
it to run tangent to the wire.   I looked on line for you tube videos  
of London and the closest I can find is the one that Derrick posted  
earlier today ... The Elephant Never Forgets ... reposted below.    
Look closely and you will see the mammoth harp.

http://www.youtube.com/watch?v=a7lK2tDglXQ&feature=related

There is a tape of Metropolitan 331 at Crich but it was a car that  
went from London to, I believe, Leeds and then came to the museum and  
was repainted as a London car.   John will be sure to correct me if  
I'm wrong.   I'm pretty sure that the pole was properly centered in  
Leeds and it was never fully restored to its London configuration.    
The museum at Crich was started in the early 1960s, a decade after  
the last London cars ran and the ones they have came home from  
somewhere else or were rebuilt from outbuildings or sheds.




On Feb 3, 2009, at 2:42 PM, Phillip Clark Campbell wrote:

>> ----- Original Message ----
>
>> From: ROBERT R ROCKWELL <w3syt1 at msn.com>
>> To: pittsburgh-railways <pittsburgh-railways at dementia.org>
>> Sent: Tuesday, February 3, 2009 10:49:36 AM
>> Subject: [PRCo] Trolley question
>>
> Mr.Rockwell:
>
> My first answer to each question is for streetcars and the second  
> one is for
> trolleybuses but there are always exceptions aren't there.
>
>> Does the trolley wheel harp or slider swivel on the pole ?
>
> No for streetcars
> Yes for TBs
> Some streetcars retrofitted with swivel harps.
>
>> Does the pole swivel in the base?
>
> Pole is clamped into the base for both streetcar and bus.
>
>
>>
>> Does the spring loaded base assembly swivel on the car roof ?
>>
> Yes, the base moves to allow movement of the pole.  There is a  
> shunt attached
> to the base so current is routed around bearings otherwise they  
> would arc, pit, and
> eventually freeze.  This shunt will limit how far the pole can move  
> but it is generally
> arranged so it can turn 180-degrees and operate from that position  
> if necessary.
>
>
> Phil
>
>
>
>
>
>