[PRCo] Re: Trolley question

[Phillip Clark Campbell]

> > From: ROBERT R ROCKWELL 

> > Does the trolley wheel harp or slider swivel on the pole ?
> 
> From: Phillip Clark Campbell <pcc_sr at yahoo.com>
> 
> No for streetcars

Pittsburgh did have at least one piece of equipment where the harp with wheel
did swivel didn't they.  This was their portable rail grinder.  To keep the line
running when grinding, rubber wheels were dropped and the grinder operated
under power to the side of the track;  the trolley wheel swiveled to allow this
maneuver.  The grinder operated up a ramp onto a flatbed trailer when work
was finished.  Early trolleybuses also had this swivel harp and wheel.


Phil



> 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