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.
Just gotta open your ears…
hisssssssssssssssssssssssssssssssssss
Mares shank…
Just be sure there isn’t an accompanying rattle! [:O]
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. [:P]
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.
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 cock and 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?
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…
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.
If your not breaking the joint you shouldn’t need to tie it down, the engines independents should hold it, mountain grades notwithstanding.
“Mares shank” is slang for walking. From Wikipedia: More obscure terms for walking include “to go by Marrow-bone stage”, “to take one’s daily constitutional”, “to ride Shanks’ pony”, “to ride Shanks’ mare”, or “to go by Walker’s bus”. Among search and rescue responders, those responders who walk (rather than ride, drive, fly, climb, or sit in a communications trailer) often are known as “ground pounders”. http://en.wikipedia.org/wiki/Walking
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 . . . [swg] >
- Paul North.
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
- Paul North.
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.