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

[Fred Schneider]

But if you overuse the track brakes, you can also wear off the  
wearing surface on them too.

On May 27, 2007, at 8:40 PM, Jim Holland wrote:

> Herb Brannon wrote:
> .
>> Maybe it was just a bad dream then. I know, I was there in the
>> operators seat. Whatever the trucks, the specs, the engineers
>> drawings, the claims of Transit Reserarch Corp., etc. the brakes
>> failed and the car glided (it was not a 50mph runaway) all the way to
>> the bottom of the hill. It was then pushed around downtown and  
>> back to
>> SHJct by another car. But then 1727 should not have crashed either.
>> That car was heading for disaster almost a decade before it finally
>> did itself in. The cars had all seen heavy usage and PATransit was
>> trying to keep them going as long as they could. SKYBUS was a dead
>> subject and the cars had to keep operating. Many modifications and
>> "experiments" along with rebuilds (mostly "cosmetic", but  
>> "mechanical"
>> to the point that the operation of the vehicle might have been
>> changed) caused many strange mechanical happenings that were never
>> fully discussed with the general public, the press, or the  
>> railfans. I
>> remember that incident quite well, it was the
>> only time I came close to being scared. I don't scare easily, believe
>> me, I don't. That trip down the hill was as close as I have come to
>> being really scared.
> .
> You have some Vivid Dreams, Herb!!!    Possibly what Boris  
> suggested ---
> air pressure insufficient for complete release of drums and they wore
> out --- track brakes should have helped and even stopped the car.
> .
> Since this Is an ImPerfect World we shall  *_Always_* have  
> accidents ---
> they can't be avoided even with the Bestest of Planning!!!
> .
> 1727 may have been a problem car but *_The__Problem_* which caused the
> accident has been positively identified and is most probably totally
> unrelated to other problems the car had.  Only time I experienced
> anything similar to non-responsive braking was an SF Baby Ten
> (Westinghouse, B3 like PRCo Interurbans)  was a car giving an operator
> trouble on pullout and since I was working the line closest to the  
> barn
> it was traded to me for pull-in.  The car wouldn't take power
> immediately but when it did come on it came on with a real Bang!  Very
> similar for braking.  Just cleared the K-line loop at Phelan so was  
> off
> revenue trackage and on pull-in trackage when the car locked up ---
> Battery low which means drums won't release.  Battery drives pilot  
> motor
> and possibly explains the slow response and Banging on both  
> acceleration
> and braking.  I could go back through my files and pull up the car
> number but that takes time.
> .
> The ex-SLPS cars in SF Muni 1101 series  (GE!!)  were prone to Total
> Brake Failure --- something in the KM switch group failed as I was
> told.  Had that happen Many Times --- hate those cars!  Can't compare
> these cars to others because they are early All-Electrics and SLPS was
> the experimental property for All-Electrics.  Acceleration worked much
> differently from the Baby Tens --- rough on the SLPS cars --- donut  
> know
> if that was a GE type problem or just the unrefined experimental  
> nature
> of these All-Electrics.  While I did not like PRCo 1725-1799 GE
> ALL-Electrics, the acceleration was not noticeably different from  
> the WH
> cars, 1700--1724, so I suspect that the problems with the SLPS cars  
> are
> from the earlier phase electrics.
> .
> .
> .
> JBH
> .
> .
> .
>> Jim Holland <PRCoPCC at P-R-Co.com> wrote: Herb Brannon wrote:
>> .
>>> 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?
>> .
>>> Boris Cefer 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
>> .
>> 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!!
>> .
>> Chust as a reminder.......
>> .
>> .......This is an ImPerfect World
>> .
>> In Fact --- EVERYTHING and _EVERYONE_ is Very Far From Perfect.
>> .
>> .
>> 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.
>> .
>> .
>> 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.
>> .
>> 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.
>> .
>> .
>> PRCo:::::::
>> .
>> 100, 1000--1199 --- Air-Applied, Spring Released Wheel Tread Brake  
>> Shoes
>> .
>> 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!
>> .
>> 1400--1564 --- Air-Applied, Spring Released Wheel Tread Brake Shoes.
>> Some converted to drums; these cars Not Plagued with slippage like  
>> the
>> 12s.
>> .
>> 1600 --- All-Electric
>> .
>> 1601--1699 --- __AS__DELIVERED__ Air-Applied, Spring Released _DRUM_
>> brakes --- extended range dynamics.
>> .
>> ..........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.
>> .
>> 1700--1799 --- All-Electric.
>> .
>> 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!!
>> .
>> .
>> .
>> Jim__Holland
>>
>>
>>
>>
>> Rise Up -- Go Cavs
>> Herb Brannon
>>
>>
>>
>>
>
>