Let's say an engineer is charging the train air system prior to departure... the compressors are working but the pressure will not rise to 90 psi (or whatever it is) and the brakes therefore won't release. He/she determines that there's probably a leak in the system. How does the crew determine where the leak is? Is there a quick way to determine where in the train the leak is located? ..or does the crew have to walk the length of the train to find the leak...
The Conductor walks the train until he/she finds it.
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Just gotta open your ears...
hisssssssssssssssssssssssssssssssssss
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
Mares shank.......
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zugmann Just gotta open your ears... hisssssssssssssssssssssssssssssssssss
Just be sure there isn't an accompanying rattle!
Surprising in this day and age there wouldn't be a tool that could pinpoint the location of the leak from the locomotive cab.. ..maybe I'll invent one and sell it to the railroads.
So the conductor would walk the length of the train to listen for the telltale sound of escaping air... sounds like alot of fun on a blistering cold winter night in the backwoods of Maine.
Ulrich Surprising in this day and age there wouldn't be a tool that could pinpoint the location of the leak from the locomotive cab.. ..maybe I'll invent one and sell it to the railroads. So the conductor would walk the length of the train to listen for the telltale sound of escaping air... sounds like alot of fun on a blistering cold winter night in the backwoods of Maine.
That's called railroading!
Now I don't know how the ECP brakes work in all of this... I know you can cut out individual cars from the head end. (just takes all the fun out of it!)
Backwoods of Maine on a blistering cold winter night or the make up track in an innercity yard on a hot summer night or across a 200 foot high bridge anytime. Ten cars, not too bad. One hundred and ten cars....eh, you do the math.
henry6 Backwoods of Maine on a blistering cold winter night or the make up track in an innercity yard on a hot summer night or across a 200 foot high bridge anytime. Ten cars, not too bad. One hundred and ten cars....eh, you do the math.
Spending all day shifting cars in a downpour... soaked way past your underbritches... couplings not making...cars not rolling when you kick them...remote engine refusing to respond...radio becoming useless due to being soaked...LOL..those are the fun days!
Sometimes it's not one large leak, but many smaller ones. Especially during really cold weather. When I was a condr, I was fortunate never to have had major air problems like this. The few times I had to find a leak it was easily found and corrected.
I've heard a few horror stories trying to find air leaks. One condr said that he and a yard utility man walked the train twice and couldn't find the leak. He said they found a couple of small ones and changed out the airhose gaskets, but still couldn't get the flow down to do the air test. They heard some air blowing at the EOT, but it wasn't near has bad has the leaks they had found and corrected. Finally, they changed EOTs and that fixed it.
Jeff
Just thinking, in a case like Jeff mentioned where the leak is not obvious, would it be worthwhile to narrow it down by going about halfway down the train, cutting off an angle$1****$2and seeing what the pressure does, then depending on the result go forward or back a quarter of the way and repeat, etc? Once narrowed down to a few cars, you concentrate on inspecting them. Would this be impractical? It would probably be time-consuming, but as a last resort?
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
Sorry, I meant to say "angle rooster"
Ah, the old "half split" method I learned in USAF electronics school.
You just want to make sure you've tied down that part of the train...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Someplace I read that when there's a "dynamiter" = a car with a triple-valve that's either defective or too quick-acting, so that it goes into emergency upon a small or no brake application, etc. - and a DPU or EOT on the back, then the approximate location of the suspect car can supposedly be determined by comparing the times when the pressure drop arrives at the front and rear ends, and then by proportions figuring about where that car is.
It might be possible to do something similar with a leaky trainline, by comparing the flow rates into the air line from the front and rear units - likely, more air is coming from the air compressor on the unit(s) that is closer to the leak, all other things being equal. But I've never tried it, and it would be only a rough approximation.
Ed - What's a "Mares shank" ?
- Paul North.
tree68 Ah, the old "half split" method I learned in USAF electronics school. You just want to make sure you've tied down that part of the train...
If your not breaking the joint you shouldn't need to tie it down, the engines independents should hold it, mountain grades notwithstanding.
Mechanical Department "No no that's fine shove that 20 pound set all around the yard... those shoes aren't hell and a half to change..."
The Missabe Road: Safety First
Paul_D_North_Jr Ed - What's a "Mares shank"
Ed - What's a "Mares shank"
OK - thanks, Ed. "Ground pounder" I knew from the military, and "daily constitutional" from various references in literature. In his novel The Great Train Robbery, the late Michael Crichton referred to the many people who walked to work in London, England as "taking the Marrowbone Express", so I would have recognized that variation. But the others are all new to me. <Checks off "Learn something new today" from daily "to-do' list . . . >
I believe the car people have portable gages that they use to test individual cars after working on their brake systems - "Single Car Test" or "SCT"; also Single Car Test Device or SCTD; also Automated Single Car Test Device or ASCTD; and also Computerized Single Car Test Device or CSCTD.
Some are pretty big and need a wheeled cart, such as this Wabtec / WABCO one (2 pages, approx. 185 KB in size):
http://techinfo.wabtec.com/DataFiles/Leaflets/ASCTD%20Quick%20Start%20Guide%20A.pdf
But others are more portable, such as this New York Air Brake Co. one:
http://nyab.thomasnet.com/viewitems/test-devices/freight-single-car-testing-device-complete
And the smaller brake cylinder test gages from Pittsburgh Air Brake Co.:
http://www.pabco.biz/shopsales.htm
Would it ever be feasable to overcharge the air a bit more to try to produce a more discernable hiss? You clearly wouldn't want to take it too high, and only keep it raised as long as necessary to avoid unnecessary wear and tear.
A occasional problem when a train makes a rear end pickup (done to maintain blocking integrity at times) is having the pickup that has been on ground air or handled by another crew having that cuts train line charged to a higher pressure than the train that is making the pick up....after the pick up is made the road power is unable to pump off the initial brake application. Sometimes it can be quite a experience in finding out that the rear end pickup has been overcharged (at least in relation to the through trains brake pipe pressure). Placing the entire train in emergency a time or two and then pumping off the emergency applications will normally cure the condition.
kolechovski Would it ever be feasable to overcharge the air a bit more to try to produce a more discernable hiss? You clearly wouldn't want to take it too high, and only keep it raised as long as necessary to avoid unnecessary wear and tear.
Never too old to have a happy childhood!
IF there's good communication, and one knows as a result that this type of load will be picked up, simply venting some or all of the air first before connecting to the main trainline would avoid this, right? Then again, with leakage being quite common in small amounts everywhere, combined with this kind of thing being possible anywhere really, wouldn't this be best as a common practice?
A little clairifacation to the original question...
If your on the road, the conductor walks the train till he finds the leak...if its a gasket in the glad hands, he changes it out with one of the spares on his key ring, if its a hose that was not laced up, he laces it up, rear anglecock left open, he closes it, air hose damaged beyond repair you close the anglecock on the car ahead and set the car out, if there is no where or way to set the car out you button up the train ahead of the problem car and proceeded at restricted speed to the nearest location where the car can be set out.
Both GCOR and NORAC have specific rules regarding this.
If you in the yard picking up a track that has been worked already and is ready to depart, you call the car department, they will ride the train on thier scooter and find/fix the problem.
If its is a outlieing yard with no car department, you walk it and find/fix the problem.
As for finding the actual leak, with 90 psi of air blowing through a 1" opening in a glad hand/hose that was not laced up, well its pretty loud, you can hear it from 10, 15 or 20 cars away, it is a very distinct sound.
As for the handheld gauges we carry them with us so when we have to pick up cars that have no ground air supply we can do a initial terminal air test.
I have my engineer charge the line as I walk to the rear, laceing the cars as I go and doing a visual check of the cars, (if your lucky they are already laced up by the industry) then we use the hand gauge to check train line pressure and to compare the rear train line pressure against the locomotive gauge, minimun pressure is 85 pis and the rear has to be withing 5pis of the head end, we then do a leak down test, allowable for us is 1pis per minute, the locomotives's compressor can easily over come that small leakage.
Once we confirm that, we perform a set and release to make sure the rear car's brakes function properly, then I have my engineer set the brakes and I walk the cars back to the head end, checking eack car to make sure the brakes have set, and doing a visual once over for broken safety appliances and any obvious bad order cars.
Interesting take on the I.T.A.B.T...
edblysard [snipped] As for finding the actual leak, with 90 psi of air blowing through a 1" opening in a glad hand/hose that was not laced up, well its pretty loud, you can hear it from 10, 15 or 20 cars away, it is a very distinct sound.
Interesting procedure otherwise - thanks.
Air leaks sufficient to apply the brakes are sufficiently unique that they can be heard in almost all noisy environments.
Paul_D_North_Jr edblysard: [snipped] As for finding the actual leak, with 90 psi of air blowing through a 1" opening in a glad hand/hose that was not laced up, well its pretty loud, you can hear it from 10, 15 or 20 cars away, it is a very distinct sound. True enough. But now imagine a much smaller leak, and in a nosiy environment such as a windy day, next to a road engine running pretty fast - or worst of all, next to a busy highway with lots of truck traffic and tire noise and loud exhausts, etc. - hence my mention of the gage. Interesting procedure otherwise - thanks. - Paul North.
edblysard: [snipped] As for finding the actual leak, with 90 psi of air blowing through a 1" opening in a glad hand/hose that was not laced up, well its pretty loud, you can hear it from 10, 15 or 20 cars away, it is a very distinct sound.
edblysard *snip* air hose damaged beyond repair you close the anglecock on the car ahead and set the car out, if there is no where or way to set the car out you button up the train ahead of the problem car and proceeded at restricted speed to the nearest location where the car can be set out.
*snip*
air hose damaged beyond repair you close the anglecock on the car ahead and set the car out, if there is no where or way to set the car out you button up the train ahead of the problem car and proceeded at restricted speed to the nearest location where the car can be set out.
Not that there's any other way to do it out on the road, but doesn't that mean you're dragging a car with it's brakes applied?
BaltACD Air leaks sufficient to apply the brakes are sufficiently unique that they can be heard in almost all noisy environments. [emphasis added - PDN]
Further, I'm now considering the 'included' problem of a much smaller leak that is just enough to exceed the allowable rate - from Ed's post above: ". . . compare the rear train line pressure against the locomotive gauge, minimun pressure is 85 pis and the rear has to be withing 5pis of the head end, we then do a leak down test, allowable for us is 1pis per minute . . ." Only 1 psi in as long as a minute could be a fairly small leak, which would be hard to hear. (I'll skip the fallacy of a long train having more places for air to leak from, because it also has more compressed air in its lines, and hence each car would have to lose its share of also about 1 psi - otherwise, the leak would be of air from multiple cars, hence more and louder and easier to hear, as you noted.)
To me, in the original poster's scenario the problem isn't that the brakes won't release, but that they either can't get enough air on the rear end, and/or get the leakage to reduce enough to do or pass the air test. Some or maybe all of the car's brakes may have actually released.
What Ed described, to me sounds like a Transfer Train air test. It's less restrictive than a full blown Initial Terminal air test, but it is also limited to trains going at or under a set number of miles, etc. Ed's version actually sounds more restrictive than Uncle Pete's version, but to be honest I haven't done one in years. I'd have to look up the requirements. I'm more used to the road brake test requirements.
An Initial Terminal test requires air pressure at the rear to be within 15 psi of the feed valve setting. If you're running a 90 lbs train line, that means you need at least 75 lbs at the end of the train to do the test. There are two methods to determine brake pipe leakage. One is if the engine is equipped with an air flow meter, then to begin the test in addition to the 75 lbs on the end you need the flow to be 60 cubic feet/minute or less. If not equipped with the meter during the time the brakes are set, you cut out the automatic brake valve and watch the engine's brake pipe gauge and how much in drops in one minute. Leakage can't exceed 5 lbs per minute. If it does, you have to have any leaks corrected and start the test over.
Air leaks on the road while moving can happen due to an air hose or brake pipe going bad. It can also happen because of a drop in temperature. It isn't unusual during very cold weather to see the flow and pressure at the rear change as the sun sets or rises.
I had an auto rack train last winter that went into emergency four times when ever the slack came in just a bit on the rear end. The air also came back on it's own each time. The condr walked the train but could never find the problem. He found one car with a real slight leak. He didn't know it, but that was causing our problem.
Each time the slack came in just a bit, the air hose would twist the glad hand just enough to allow enough air to escape through the cold gaskets to put us into emergency. Once in emergency the slack would pull out enough to reseat the glad hands. (It's problems like this that make me cringe at the thoughf of 10000 foot DPU auto rack trains.) After the sun came up and the air temp rose a bit, we stopped going into emergency but would lose 10 or 12 lbs on the rear end.
I told the outbound engineer about this when we changed out. A few days later I saw him and he said he had no problems and the rear end only varied about +/- one pound the whole trip. The daytime sun had warmed up the gaskets enough to seat them properly with the slack in or out.
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Paul,
You would simply bleed off the air from the remaining cars with the bleed rod...no air at all in the cars and they roll free.
edblysard Paul, You would simply bleed off the air from the remaining cars with the bleed rod...no air at all in the cars and they roll free.
You don't carry runaround hoses?
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