[PRCo] Re: Drum__Brakes_--_All-Electrics,__etc........

[Jim Holland]

Herb Brannon wrote:
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> When mechanical 'things' (in this case a 1945 PCC streetcar, still 
> operating in 1975-76) get to a certain age, like humans, they start to 
> fall apart. Yes, it was the "Spirit of '76" car, and it had a bad air 
> leak. It would not have mattered if it would have had every type of 
> air applied brake known to mankind, it still would not have stopped 
> without any air pressure to apply the brakes. That brake system (air 
> applied/spring release), in my opinion, was one of the more stupid 
> systems devised. Couldn't at least one of the scores of engineers 
> working on the PCC project thought far enough to realize that a spring 
> applied/air released system would have been safer ???? They thought 
> enough to put a 'hand brake' on the car, why not a "fail safe" braking 
> system?
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> Boris Cefer <westinghouse at iol.cz> wrote: Are you sure, Herb? 1776 was 
> formerly an interurban car with B-3 trucks and spring-applied drum 
> brakes with air actuators (pressure-releasing).
>
> B
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As Boris Mentioned, The Bicentennial Car 1776 is ex-1616 and is thus 
equipped with B3 trucks.  ALL  PRCo B3 trucks are *_Spring-Applied_* 
Drum Brakes so a loss of air pressure with 1776_ex-1616 should have 
caused the drums to set up automatically --- i.e., air pressure is Not 
Used to stop  ({[pat]})  1601s renumbered as 1776-1781 --- Springs apply 
the brakes on these cars!!
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Chust as a reminder.......
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.......This is an ImPerfect World
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In Fact --- EVERYTHING and  _EVERYONE_ is Very Far From Perfect.
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That being said, the PCC is Still An Engineering Marvel and was Very 
Well Suited for the job it had to perform.  Even into the 1950s the PCC 
could outpace the average automobile on the road from a dead stop.  The 
PCC books indicate that the accident rate went way down with PCCs as 
compared to older conventional cars because of the increased performance 
and in spite of the Increased Speed of the PCC --- the standard PRCo 
low-floor cars had a top speed of only 25-mph until many were rebuilt 
for speeds comparable to the PCC.
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The Hand Brake was to compensate for the lack of Fail Safe as were the 
track brakes --- get the car stopped using track brakes // hand brake, 
pop the dead man to keep the track brakes applied, jump out of the car 
and chock it!  Loss of Air Pressure is an occasional & UnUsual failure, 
not routine, and the air gauge should give the op indication that a loss 
is occurring so he can Still Safely Stop The Car before total loss.  I 
rode the cars All The Time and Never experienced an air failure and 
remember Only One Operator mentioning such.
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As Schneider mentions, the All-Electrics with spring applied drums are 
fail safe --- but  *_Apparently_*  Not All Of Them.  The ex-TTC, ex-KCPS 
cars that came to SF during subway construction were GE with GE brake 
actuators and am told that when the MG is shut off, so are the drum 
brakes and the car will roll on a hill.  Thus the flange marks on 30th 
from Judah to Irving where a dead car was spotted and ran away!  I 
operated these cars but never shut down the MG except in the yard so am 
not all that familiar with them.  They were Very Smooth Operating cars 
as compared to Muni --- brakes felt Very Soft and as if the car would 
never stop but they stopped Just As Fast as a Muni car but Much More 
Smoothly.
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PRCo:::::::
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100, 1000--1199 --- Air-Applied, Spring Released Wheel Tread Brake Shoes
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1200--1299 --- Spring-Applied, Air Released Wheel Tread Brake Shoes.  
Many 12s had brake shoes removed and drums applied.  Cars with drums had 
a tendency to roll back when stopping upgrade.  Thought Izzy Reichert 
was going to have an heart attack when that happened to him on the 
42-Dormont!
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1400--1564 --- Air-Applied, Spring Released Wheel Tread Brake Shoes.  
Some converted to drums; these cars Not Plagued with slippage like the 12s.
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1600 --- All-Electric
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1601--1699 --- __AS__DELIVERED__ Air-Applied, Spring Released _DRUM_ 
brakes --- extended range dynamics.
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..........For Those 1601s Converted to Interurbans with B3s the Drums 
are Spring-Applied, Air-Released!  Remember___ 1613 and 1614 had 
experimental B3s --- believe that these were Spring-Applied - Boris??  
But Both 1613 and 1614 had B2s reinstalled in the 1950s and it is 
*_Presumed_* that they reverted to air-applied, spring released drums.
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1700--1799 --- All-Electric.
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It always *_Seemed_* to me that the 1601-Interurbans were never going to 
stop but they did and probably just as good as any other car  (possibly 
not unlike the ex-KCPS cars in SF!)  But the 1601-City Cars *_NEVER_* 
gave such an impression --- they were peppy, powerful cars!!
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Jim__Holland