[PRCo] Re: Braking Systems

[Fred Schneider]

So do I.   Basic that is.   When you work with steam locomotive and  
old wooden coaches, basic is all you get.   You might also wish to  
track down some of the mechanical people from the Illinois Railway  
Museum, Boris, because they have cars from the Chicago, North Shore  
and Milwaukee RR; and from the Chicago, Aurora and Elgin.   Both of  
these ran long interurban trains of cars fitted with automatic  
brakes.  Orange Empire also has equipment from Pacific Electric,  
which used automatic air systems.  Branford has a flock of New York  
subway cars which also qualify.   I've run a CA&E interurban car at  
RTY and a PE Blimp at Perris but that is as far as it goes.   I  
imagine you might find some schedule AMUE apparatus on former  
Sacramento Northern cars at Perris as well.   Illinois Terminal  
probably also and some of their cars are at IRM.    You might also  
write to some of your Boston friends at Seashore.

INSTRUCTION DEPARTMENT:  For those that do not understand....    
Straight air systems were OK for streetcars (and buses and trucks)  
but not OK for trains.   Straight air implies that the brake valve  
admitted air directly from an air reservoir or holding tank into a  
brake cylinder, which in turn moved a piston in the cylinder and  
associated rods to apply brake shoes to stop the car.   This worked  
fine for a single car.   The problem surfaces when running trains.    
What happens if a train splits into two sections.   You wish to apply  
brakes and you cannot because the brake hoses are torn apart where  
the train came apart.  The motorman tries to put air into the brake  
pipe and it simply flows out the end of the pipe.

Automatic air schemes have air tanks under every car.   The  
compressor (or air-pump in steam locomotive terminology) or  
compressors on every car charge the train line and thus the tanks on  
every car.   The train line is used for two purposes:  1) to charge  
or fill the individual tanks on every car, and 2) to control  
braking.    Each car has its own brake valve called a triple valve.    
When the engineer's valve is placed in release,  air flows through  
the train line and charges all the tanks under every car.  At the  
same time the triple valve connects the brake cylinders to the  
atmosphere to release brakes.      If the engineer makes a brake pipe  
reduction in pressure,  for as long as air is flowing out of the  
pipe, the triple valve will connect the reservoirs under the cars to  
the brake cylinders, thereby applying brakes.    So what happens if a  
train splits into two halves on rough track ... and I've seen it  
happen on the CNJ ... the air system simply torpedoes.  All the air  
dumps out of the brake pipe, and all the air in the car reservoirs  
goes into the brake cylinders.  The air system goes into emergency  
application.    And the water glasses slide off the tables in the diner.

To make high speed applications smoother, an electrical interface was  
used on interurban and subway equipment, probably as far back as  
1904-1910.   In this manner all brakes went on at the same time in  
every car (remember, electricity travels at 186,000 miles per second)  
instead of going on one car at a time.  This allowed much faster  
operating speeds.

There were two early bulletins done by Central Electric Railfans  
Association in the 1940s that explained some of this.   They are on  
the top shelf Boris and not only do I need a ladder to get to them  
for reference, but you know too just how bad this room looks ... just  
getting a ladder in here is problematic.


On Oct 19, 2005, at 3:36 PM, Boris Cefer wrote:

> The air brake systems used by railroads and the history of these  
> may be very
> interesting. Unfortunately, I have only basic knowledge in this  
> area. There
> were more systems than we can imagine.
>
> B
>
> ----- Original Message -----
> From: "Fred Schneider" <fwschneider at comcast.net>
> To: <pittsburgh-railways at dementia.org>
> Sent: Wednesday, October 19, 2005 9:14 PM
> Subject: [PRCo] Re: Braking Systems
>
>
>
>> I don't remember a signal light on the 1700s.   The Philly 2700s do
>> have a "shaft brake" indicator light.   I think this was one of those
>> customer options.    If the car was drifting with the pedal latched
>> down, the shoes were worn or the drum brakes were not applied.   Who
>> needed a light...
>>
>> Same deal with the air-PCCs.   Baltimore installed brake pipe
>> gauges ... huge mothers, 4 inch gauges.   Told you that the brake
>> shoes were applied.   Those were the only air-PCC cars I ever saw
>> with brake pipe or brake cylinder gauges.   Every other one I rode or
>> ran simply had a reservoir gauge.    Again a customer option.
>>
>> Most older U. S. streetcars also only had reservoir gauges but a few
>> had double hand gauges, with one hand showing the brake pipe and the
>> other the brake reservoir.    The Baltimore Peter Witt (and I'm sure
>> some other safety cars but I have no clue how many) mounted the air
>> gauge on a separate emergency reservoir instead of the main
>> reservoir.   The logic was that the main reservoir charged first and
>> then the emergency reservoir, so if the ER gauge showed enough air,
>> both tanks were charged.
>>
>> Digression applies only to straight air and not train air (or
>> automatic air) systems which required separate gauges for both
>> reservoir and brake pipe because they were independent of each other.
>>
>> I am not competent to talk about the more recent electro-pneumatic
>> schemes after the 1960s.    Wish I was.   Newest locomotive I ran was
>> a 1948 GE 44 ton diesel.   Oldest was a 1905 Juniata Shops built
>> 4-4-0.   So you know my range of knowledge.   And triple valves from
>> P up to UC.
>>
>> On Oct 19, 2005, at 2:53 PM, Boris Cefer wrote:
>>
>>
>>> Didn't the 1700s have a drum brake signal light? The motorman had
>>> to notice
>>> that. What was the practice of motorman training?
>>>
>>> B
>>>
>>> ----- Original Message -----
>>> From: "Fred Schneider" <fwschneider at comcast.net>
>>> To: <pittsburgh-railways at dementia.org>
>>> Sent: Wednesday, October 19, 2005 8:16 PM
>>> Subject: [PRCo] Re: Braking Systems
>>>
>>>
>>>
>>>
>>>> Yes.   Broken motor lead so the dynamic brakes failed.   Because  
>>>> they
>>>> failed, all the motorman had was drum brakes.   He was young,
>>>> inadequately trained, and didn't understand why he was sliding
>>>> through all the stops on the way in that morning.   And the problem
>>>> was compounded because PAT removed the timed derail at South Hills
>>>> Junction .... had it been there, the car would probably have  
>>>> been on
>>>> the ground at the top of the hill instead of slamming into the P&LE
>>>> station.   But if memories are short and we can't remember that we
>>>> had two previous runaways in the tunnel, well, you get the picture.
>>>>
>>>> On Oct 19, 2005, at 12:37 PM, Boris Cefer wrote:
>>>>
>>>>
>>>>
>>>>> Perhaps the most tragic story of a streetcar which lost its brakes
>>>>> (well, in
>>>>> the PCC era) was an accident of 1727 at Station square on 28th
>>>>> October 1987.
>>>>>
>>>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
>