# FILLING AIR BRAKE SYSTEM



## John J (Dec 29, 2007)

I got this thought from another post a bout a 7 mile long string of cars.

Does anyone know the average length of a train?

How long does it take to fill a train to release the brakes so that it can move? 

Do they use Screw type compressors or Piston?


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## DKRickman (Mar 25, 2008)

Average length varies wildly, based on the type of train and the location. On NC, the average coal train is about a mile long, the average intermodal train is between 1 and 2 miles long, and mixed freight usually runs somewhere around a mile as well.

Time for release can vary a lot, as well, depending on the temperature. The colder it gets, the longer it takes to build up air pressure. Short trains (less than 50 cars or so) are almost instantabeous. By contrast, I brought one in this morning, 8059' long, ad it took 20 minutes or so to pump the brakes up. 


The compressor question is easy! All the compressors I've seen are three piston designs. Some are powered by an extension of the crankshaft, and others are powered by an electric motor.


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## ohioriverrailway (Jan 2, 2008)

Longer if you've got a bunch of ratty old general service gons that have gladhands that leak like a sieve.


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## Bill Swindell (Jan 2, 2008)

Yes but if the hoses leak like a sieve, it won't pass the leakage test so you can't use them in a train.


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## coyote97 (Apr 5, 2009)

Thats one of the things i learned while doing my hobby-career.

Whilst i didnt know about airbrakes at all, operating them is another question. Learning about was very interesting for me.

German railroaders say: driving is easy for everyone, braking is not.


The time it needs to pump up a train depends on the train (for sure) and on the pump. Once we had a little loco with a small pump just to fill one waggon or at max. two. (Thats ok, because we have a 3% incline and the loco has 50HP....but how about going downwards???)
we had to fill a 7 waggon-string (wow....worlds longest train  ), but the little loco pumped for 15 minutes to fill it.

Regarding this question i once discovered why some locos had double-pumps. Just a question of the number of driven airbrakes. The locos here in our midland-landscape hadnt additional pumps, though we had steep and long inclines. And "extra"-equipment always was for heavy duty (in my mind). But its clear, the steeper the lines, the shorter the trains: the lesser the pump-capacity needed.

The problem is, that even on not suspected locos the copressors can be THAT powerful (we here had that in the BR 111), that a traincut isnt registered and the brakes on the loco-sided halftrain dont work. The compressor fills in so powerful, that it just comes to a small pressure-fall. For sure a mindful driver will notice once, but it is proofed that it can happen. 

Interesting question, too, is, what is the pressure doing in the car-line while braking or filling? tests gave an interesting result: pressure-pikes are wandering around like a wave going forward and back through nearly the whole train sometimes making strange operation on several brakes. So thats the main reason long trains cant stop immediately: the pressure needs to be brought down slowly so that it can change similarly along the whole train.
Today most cars have modern brake-equipment, its much easier now. But there was time while very simple airbrakes and modern one were on duty. Therefore we had a special order here in germany not to mix a train up wildly with different brakes. The slow ones had to be near the loco, while the fast once should have been switched in at the back.

German railroads dont really know about long trains.....but the economic pressure grows, and they are thinking about going over 120 axles regularly. Therefore they are looking for a additional electrically controlled brake that allows to bring a brake-command to the valves in the whole train in zero-time.

Is there anything similar in the US?
Or perhaps on duty, now?


Frank 


btw: braking and airbrake is my personal joke when i look at hollywoods art to bring trains into movies: THAT much to laugh about! The airbrake-system on trains is too safe for the directors in the movie-factories!!!


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## coyote97 (Apr 5, 2009)

ahm...oncemore forgot about the original question:

I dont know about screwtyp compressors, but perhpas my friends do...i will ask.

Filling and releasing is a problem, when not standing even......

....for not spilling the valuable time of locos (3 Million Euros one) we have filling stations on our grand switching-yards.
When a train is completed, the airhoses are fixed and then the filling station will prepare the train. The switching-man even can make a full brake-test, so that, when the loco is coupled, a simple brake-test is enough (just takes a minute or two).


Frank


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## Semper Vaporo (Jan 2, 2008)

A few years ago, on a sub-zero late evening, I stopped at my favourite train-watching spot at the east end of a railyard here, to eat a late supper. I was about to leave due to the cold and not wanting to burn gas to keep warm in my car, when on my radio scanner I heard a west-bound train call the yard asking if it was okay to come in and get some cars that had been prepared for him. The Yard-Master said okay but there were "a couple more cars than what you have been told." So I decided to stay and watch the "action".









The engineer was already bringing his train to a stop east of the yard to uncouple the engines to come into the yard to get the string of cars. They brought the engines in, went around the new consist and spent quite a while pumping up the brakes. Then they pushed the string back to their present train.

Unfortunately, the number of cars they added to the train left the engines "in" the grade crossing when added to where the original consist was left. This blockage of that street was a common occurance and a consternation to many people that used that road as a "quick shortcut" to/from the airport! The RR was often in trouble with these motorists!

It took 20 minutes to get the air pumped up on the train! Amidst lots of automotive horn honking and shouts from the drivers. The County Sheriff came just about the time the train started moving, so all he did was turnaround and leave. Just as he was receding from sight the train went into emergency... I believe it was a problem with what is known as a 'kicker"... a brake triple-valve that accidently trips and dumps the brake line which sets ALL the brakes. This of course stopped the train immediately!

This left the train blocking the crossing while the brake pipe was pumped-up again. In low temperatures this takes a long, long time especially when the whole line has been dumped in "Emergency". He sat there for close to 45 minutes! On the scanner I could hear the conversations between the train crew, the regional Dispatcher and the Yard Manager. The Dispatcher began to make more urgent calls to the train asking when he could move as they were getting calls from local Law Enforcement about the blocked crossing! Even though the first blockage was because they had added additional cars to the "pick up", the Engineer was verbally reprimanded for not leaving his train farther from the yard so as to leave room for the cars to be added to it, but was also let off the hook for the "Kicker" causing the 2nd of the problem... the Dispatcher was "sympathetic" but also stern in his requirement to "get your train moving!"

A motorist came to my car and banged HARD on my window (scared the bejeebers out of me as I didn't see him comming! Very glad my drink cup was empty!). He yelled at me: "I have been waiting for over 2 hours to get through here!!!" (Not true, at this point it had been only about 45 minutes total! Which, granted, is too long.) I explained what was happening and why the train was not moving... and that I did NOT work for the RR and thus could not move the train even if it could be moved.

I could see between the train cars when the City Police came to the yard office and uniformed officers enter the building. About the same time a City Police Car showed up on my side of the tracks. That Officer approached my car and TOLD ME! in no uncertain terms to "MOVE THAT TRAIN!"!!!

I explained that I do not work for the railroad. Then I explained the problem to the Officer as I understood what had happened and what I was hearing on the radio. He calmed down and went to talk to some of the irate motorists and then left.

Then the County Sheriff came again. He approached my car and DEMANDED that I move that train or I would be "subject to arrest"!!!!!!

I giggled and said, "Well, oh dear, I guess you'll just have to arrest me... That is a Diesel on the head of that train and I only know how to run a Steam Locomotive so I don't know how to move it... besides, even if I did, you'd have to arrest me for stealing the train, 'cuz I don't work for the railroad."

He replied, "I see you out here in all kinds of weather and YOU DON'T WORK for the railroad? SHEESH!" Then he shook his head and stared at the ground while I explained to him what I knew of what was happening and that I was sure the train would be moving as soon as the brakes were released, but that according to the chatter I had last heard on the scanner that they had another "5 pounds to go" (which took about 15 minutes! I could hear the Engineer calling the Dispatcher with updates EVERY POUND of increase!)

As soon as it was at the allowable pressure the train started moving and it took another 5 or 6 minutes to clear the crossing. The crossing was blocked about 1 hour and 40 minutes and I counted about 70 autos in the line going over the crossing afterward. I then went home, secure in the knowledge that the Sheriff was sure I was nutz!


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## John J (Dec 29, 2007)

Sheriff thought you were nuts? 

When you nuts they never aske you to explain anything


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## Totalwrecker (Feb 26, 2009)

I've found that they ask me to shut up.... 

Semp are you wearing your hogshead hat? Seems like you're doing something to look the part. 


John


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## Semper Vaporo (Jan 2, 2008)

Posted By Totalwrecker on 29 May 2010 10:53 AM 
I've found that they ask me to shut up.... 

Semp are you wearing your hogshead hat? Seems like you're doing something to look the part. 


John 

Being there so often makes for familarity (which breeds contempt?), but I don't usually wear a hat at all.

The "give-away" is probably the 5 bumper-stickers:

WARNING! 
I brake for trains

Just another 
Ferroequineologist 
out chasing trains

I (Heart) Trains

My other vehicle is a 
Steam Locomotive

Semper Vaporo


and my license plate:

STM PWR


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## Totalwrecker (Feb 26, 2009)

Yep mighty compelling 'clues'! You should know better than to leave your train on the crossing! 

Poor engineer! How long is a 'few' extra cars? 

Me? I've just got an aluminum coupler stuck in my reciever hitch. 

John


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## jgallaway81 (Jan 5, 2009)

He's just lucky he didn't have to inspect the train himself. I once had to make a 5,000ft pickup that had been off air for more than four hours. This in addition to the 8,000ft my train already had. 

Despite having two locomotives' compressor pounding away, it took well over an hour to initially charge the train, and during the inspection, I had to have the engineer recharge three times to check brakes that failed to apply initially... all told, we had a crossing blocked for nearly four hours.

And the crossing was the entrance to a prison with a work-release program!!!!!


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