[PRCo] Re: Fineview___PCCs

[Harold Geissenheimer]

Greetings to Boris, Fred, Jim and all
Thank you all for your detailed discussions about
PCC braking..  I learned a great deal from you all.
Its not a subject that I was ever involved in.

I have the front page of a Pgh Press Sunday Mag with a
beautiful painting of  the Fineview trolley on a steep grade,
Beautiful.  It may have been America's most spectacular
trolley. 

Harold Geissennheimer

Boris Cefer wrote:

>I should mention following to justify the three rates of drum brake. The
>intent of variable drum braking wasn't to provide variability within those
>4/10ths of a second. It would be a nonsense. The three drum brake rates were
>there to provide final stop with an adequate deceleration (approximately, of
>course) for each brake pedal position after the dynamic braking faded, with
>a fully automatic sequence and without any pedal movement. Each particular
>range of dynamic braking was followed by an adequate final stopping.
>Moderate dynamics - moderate final stop; full service dynamics - full drum
>stop.
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>>Regarding variable rate drum brakes:  drums were generally used only in
>>conjunction with extended dynamic brakes in North America, which extended
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>the
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>>dynamic brake capability down to about 1 mph or about 1.5 feet per second.
>>Given a normal braking rate of around 4 miles per hour per second, the car
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>is
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>>going to stop in about 4/10ths of one second after the drums come on,
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>which is
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>>faster than any operator could adjust the pedal depression to change a
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>braking
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>>rate.  Regardless of such reality, General Electric did build variable
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>rate drum
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>>brakes which, to me, seems somewhat lame.
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