[PRCo] Re: Fineview___PCCs

[Boris Cefer]

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.


> Regarding variable rate drum brakes:  drums were generally used only in
> conjunction with extended dynamic brakes in North America, which extended
the
> 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
is
> going to stop in about 4/10ths of one second after the drums come on,
which is
> faster than any operator could adjust the pedal depression to change a
braking
> rate.  Regardless of such reality, General Electric did build variable
rate drum
> brakes which, to me, seems somewhat lame.