PCC Speed Demon!

[Fred W. Schneider III]

The speed at with counter electromotive force in the motor matches that imposed
on it from the outside, usually calculated or measured on level tangent track at
600 volts for a streetcar.  Since you are new to this message system, we had a
long discussion earlier.  For a PCC built in 1936 and weighing less than 36,000
lbs, it was calculated at 42 miles per hour but it took more than a mile to get
there.  A 25 mph speed was usually possible in a city block, 15 by the time you
got through the intersection.  The acceleration was linear up to about 20 miles
per hour; all the field shunts were probably in by that point and acceleration
trailed off rapidly.  Of course up hill will be slower ... something like 12 mph
after running for ever on a 6% grade.  And faster downhill.

Harold Geissenheimer wrote:

> Greetings
>
> As I remember, PCC cars when built were supposed to have a "balancing" speed
> of 44 MPH.
> What does "balancing" speed mean?  Harold Geissenheimer
>
> "Fred W. Schneider III" wrote:
>
> > Remember our discussions about how fast PCC cars run?  The 90 mile an
> > hour car on Ardmore Boulevard?
> >
> > I had my first chance this morning to run former PTC 2711 at the
> > Pennsylvania Trolley Museum.  It very conveniently has a speedometer,
> > which was installed by SEPTA during the GOH program.  Floorboarded out
> > of the Arden loop ... downhill ... by Yanovich stop (maybe three city
> > blocks) we had less than 25 miles per hour.  Admittedly, there is no
> > feeder cable up there and we were a mile from the substation.   As the
> > speedometer wrong?  I doubt it.  It was taking about 3.5 seconds between
> > line poles about 50 feet apart.  My witness was Greg Walz.