I'm not sure of the 'country of origin' of the derailment detector, but it's in use on more than just the Swiss railways. From slide 10 of 18 at:
http://www.otif.org/fileadmin/user_upload/otif_verlinkte_files/05_gef_guet/03_AG-Entgleisungsdetektion/2014_10/CE_GTDD_2014-A_Annex_V_Presentation_Knorr-Bremse_E.pdf
Switzerland - 1,800+/- of the "EDT100" model, 713 of the "EDT101" model
France 114
Germany 720
Slovenia 161
Slides 15 and 16 have 2 case studies where these detectors operated during slow-speed derailments.
- Paul North.
Slightly off topic is a question. Is any of the oil train product and / or pipeline going back into the strategic oil reserve ? Wasn't there a withdrawl several years ago ? Seems like a good time to " fill er up ". Naturally any Bakken or other product volitility would need to be delt with.
The broken record keeps playing the same song over and over and over.
Norm
EuclidOne example would be replacing 150 year-old compressed air braking technology with electronically controlled pneumatic braking on the new tank cars now coming online.
I love that. Notice how the author replaced air with pneumatic to make it sound all hi-techy!
People fall for that crap, I guess.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
zugmann Euclid One example would be replacing 150 year-old compressed air braking technology with electronically controlled pneumatic braking on the new tank cars now coming online. I love that. Notice how the author replaced air with pneumatic to make it sound all hi-techy! People fall for that crap, I guess.
Euclid One example would be replacing 150 year-old compressed air braking technology with electronically controlled pneumatic braking on the new tank cars now coming online.
Yep - 150 year old pneumatic braking to be replaced with compressed air and electricity - how Edisonian! Where is Nichola Tesla? Still with George Westinghouse?
Never too old to have a happy childhood!
To be fair, they just spelled out ECP instead of using the initials. At least at first. Probably so the uninitiated would know what ECP stands for.
Jeff
Also misleading. While the prinicples of the air brake are the same, it isn't the same beast. Control valves have been improved upon (quick release and apply features).
1) ECP brakes to shorten the train stopping distance due to their instant application.
2) Empty/Load sensors to further shorten train stopping distance by allow a higher brake force on loads.
3) Derailment sensors to further shorten train stopping distance by applying brakes when a derailment occurs instead of waiting until the train parts; and to prevent derailments from becoming pileups.
4) Differential braking to further prevent derailments from becoming pileups.
If I remember correctly, the electrically-operated or -assisted air-brake valve predates the invention of the 'quick-acting' triple. Some people seem to think that "150-year old pneumatic braking" is a primitive system, rather than an innovative approach to combining charging and signaling in a one-pipe air system. A
As noted, the additional time given by ECP at each car vs. what is achievable with fast-acting triples is not the advantage of the system for freight trains. If the speed with which a release proceeds to high braking effort is a concern, devices similar to the trainline-release portion of a FRED can be cut into the trainline every few cars -- likely corresponding to the 'unit' consists that are the right length for loading/unloading facilities -- and produce so near the effect of individual valves as not to matter. (This begs the question whether quick application of high braking rate is actually desirable; I happen to think it is not in a great many circumstances, including just about any derailment or damaged-track scenario).
The benefit of ECP as far as I am concerned is that the technology allows graduated release and modulated proportional re-application on an individual-car level. It would be possible to do a version of this with a two-pipe pneumatic system, of course; the big question always having been how you make ECP-equipped cars compatible with single-pipe Westinghouse.
I had thought that the point of this special oil-train system was that whole consists were going to be designed that were not expected to work in interchange service directly, and that it would be cost-effective (considering the alternatives!) to provide all the special controls to make the trains 'safe' via the special safety provisions. In my opinion it makes little sense to take away or cripple important component subsystems of such an approach in order to preserve less important aspects of operation.
jeffhergert oltmannd ECP braking just replaces the "brakes on" signal, that now runs at nearly the speed of sound down the trainline, with one that operates at near speed of light. All the other fancy stuff that could be done, like load/empty variable braking, car health monitoring, ride monitoring, bad journal bearing detection, are not part of basic ECP. ECP provides smoother braking because brake actuation can be faster (no need for damping that keeps pneumatic control valves stable) and will apply simultaneously on every car. You get faster recharge because the trainline just provides one fucntion - fill the reservoirs - and can be run "wide open". You get much shorter braking distances at low speed, but not very much improvment at higher speeds. One thing I don't know - how will an ECP train know to go into emergency at a break-in-two? Loss of comm? I think the loss of air pressure in the train line (even though it is now a "supply" line in ECP)if it parts will still cause the brakes to go into emergency. Jeff
oltmannd ECP braking just replaces the "brakes on" signal, that now runs at nearly the speed of sound down the trainline, with one that operates at near speed of light. All the other fancy stuff that could be done, like load/empty variable braking, car health monitoring, ride monitoring, bad journal bearing detection, are not part of basic ECP. ECP provides smoother braking because brake actuation can be faster (no need for damping that keeps pneumatic control valves stable) and will apply simultaneously on every car. You get faster recharge because the trainline just provides one fucntion - fill the reservoirs - and can be run "wide open". You get much shorter braking distances at low speed, but not very much improvment at higher speeds. One thing I don't know - how will an ECP train know to go into emergency at a break-in-two? Loss of comm?
ECP braking just replaces the "brakes on" signal, that now runs at nearly the speed of sound down the trainline, with one that operates at near speed of light.
All the other fancy stuff that could be done, like load/empty variable braking, car health monitoring, ride monitoring, bad journal bearing detection, are not part of basic ECP.
ECP provides smoother braking because brake actuation can be faster (no need for damping that keeps pneumatic control valves stable) and will apply simultaneously on every car.
You get faster recharge because the trainline just provides one fucntion - fill the reservoirs - and can be run "wide open".
You get much shorter braking distances at low speed, but not very much improvment at higher speeds.
One thing I don't know - how will an ECP train know to go into emergency at a break-in-two? Loss of comm?
I think the loss of air pressure in the train line (even though it is now a "supply" line in ECP)if it parts will still cause the brakes to go into emergency.
Thanks, Jeff. That makes sense to me now that I think about it. Each car would have a pressure switch (or transducer) on the brake pipe.
I think it would take a peristent lack to comm to cause a braking failure. Not suitable for break in two protection. Getting an electronic trainline to function reliably is going to be some trick.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Euclid According to the FRA final report on ECP brakes for freight service, August 2009, ECP brakes reduce the stopping distance to 40 to 60% of the stopping distance with conventional air brakes. They cite a test of a loaded 100-car train moving at 50 mph. With conventional air brakes, the train took 4,100 feet to stop. With ECP brakes it took 2,500 feet to stop. A shorter stopping distance means that the cars behind a derailment and developing pileup will lose their kinetic energy sooner; and will therefore shove fewer cars into the pileup.
Identical braking ratio on the cars? I doubt it. ECP doesn't develop more braking force in and of itself.
oltmannd jeffhergert I think the loss of air pressure in the train line (even though it is now a "supply" line in ECP)if it parts will still cause the brakes to go into emergency. Jeff Thanks, Jeff. That makes sense to me now that I think about it. Each car would have a pressure switch (or transducer) on the brake pipe. I think it would take a peristent lack to comm to cause a braking failure. Not suitable for break in two protection. Getting an electronic trainline to function reliably is going to be some trick.
oltmannd Euclid According to the FRA final report on ECP brakes for freight service, August 2009, ECP brakes reduce the stopping distance to 40 to 60% of the stopping distance with conventional air brakes. They cite a test of a loaded 100-car train moving at 50 mph. With conventional air brakes, the train took 4,100 feet to stop. With ECP brakes it took 2,500 feet to stop. A shorter stopping distance means that the cars behind a derailment and developing pileup will lose their kinetic energy sooner; and will therefore shove fewer cars into the pileup. Identical braking ratio on the cars? I doubt it. ECP doesn't develop more braking force in and of itself.
Euclid According to the FRA final report on ECP brakes for freight service, August 2009, ECP brakes reduce the stopping distance to 40 to 60% of the stopping distance with conventional air brakes. They cite a test of a loaded 100-car train moving at 50 mph. With conventional air brakes, the train took 4,100 feet to stop. With ECP brakes it took 2,500 feet to stop. A shorter stopping distance means that the cars behind a derailment and developing pileup will lose their kinetic energy sooner; and will therefore shove fewer cars into the pileup. Identical braking ratio on the cars? I doubt it. ECP doesn't develop more braking force in and of itself.
I never said that it develops more braking force. It stops the train quicker because it takes less time to apply the brakes.
Figures lie. Liars Figure.
Those with an agenda present figures for their agenda.
Euclid oltmannd jeffhergert I think the loss of air pressure in the train line (even though it is now a "supply" line in ECP)if it parts will still cause the brakes to go into emergency. Jeff Thanks, Jeff. That makes sense to me now that I think about it. Each car would have a pressure switch (or transducer) on the brake pipe. I think it would take a peristent lack to comm to cause a braking failure. Not suitable for break in two protection. Getting an electronic trainline to function reliably is going to be some trick. According to that report on the NS testing of ECP brakes on unit trains, it says that the function of the air line with ECP brakes is only to supply air to the reservoirs. It plays no part of any type of brake application.
I believe it's a safety feature. The loss of all, or a significant amount, of air pressure in the supply line would in effect be a red flag to the system that something is wrong. (This doesn't just happen when the train parts. It could also happen because hoses part, a hose or the train pipe itself bursts.)
I would guess it would also work in case the train line is blocked somewhere in the train. The portion of the train behind the blockage would sense that the pressure is dropping as the the air supply in the reservoirs is used up. Without a constant resupply, the air supply could drop to where you have reduced or no braking power available on that portion of the train.
Therefore I would think sensing no or a very reduced air supply ECP brake valves would trigger an emergency application. Kind of like passenger brakes will go to emergency if the train line pressure on the conventional air brake system drops below 20 psi.
EuclidSenators Maria Cantwell (D-WA), Patty Murray (D-WA), Tammy Baldwin (D-WI) and Dianne Feinstein (D-CA) have introduced the Crude-By-Rail Safety Act of 2015. It requires a variety of improvements to tank cars, including the installation of ECP brakes.
They going to start with the miles of new oil trains stored on shortlines? The traffic has really died down with the oil prices.
Euclid Jeff, I see your point. It seems like both the wire and the air line parting would each tell the ECP system to set the brakes if the train parts. But even if the air line loses pressure just from a leak, surely the ECP system is going to react and do something in response. I have another question. Say a loaded 100-car unit train is moving at 40-50 mph, and it breaks in two 25 cars back from the head end. Is there any tendency for the hind end cars to catch up with the head end cars after they part because all of the brakes will set up quicker on the 25 head end cars than on the 75 cars behind the break in two? It seems like the 25 cars would slow down faster than the 75 cars, but I am not sure about that.
Sure, the ECP system may give warning to allow the engineer to do something if pressure is dropping or reaches a specified pressure level. (Would probably just go into emergency for a complete loss of pressure.) However, with the current climate where railroaders are either thought to be incapacitated, unattentive, or incompetent, there's going to have to be a feature that acts if the engineer doesn't. Otherwise, all the electric and mechanical do-dads added are for nothing.
Whether the rear portion of the train catches up with the front probably depends on conditions at the time. Also on type of train, etc. Any time I had to walk a train where we parted, there has always been a gap. However, as the cab camera video of the train derailing shows, there can be times when it happens. There are also stories about a train going into emergency at night or in the fog, the crew just finding a parted hose upon inspection. They reconnect the hose and go on their way. At the next yard they find they are a car short, or a section gang the next day finds a car in the ditch. (I 've heard the story enough to think it's a tall tale, but it probably has happened once.)
Also, engines can be equipped with a 20 second delay before the PCS opens and stops the engine(s) from producing power from a train initiated emergency application. This is to allow the head end to try to pull away from the rear end.
jeffhergert Euclid Jeff, I see your point. It seems like both the wire and the air line parting would each tell the ECP system to set the brakes if the train parts. But even if the air line loses pressure just from a leak, surely the ECP system is going to react and do something in response. Sure, the ECP system may give warning to allow the engineer to do something if pressure is dropping or reaches a specified pressure level. (Would probably just go into emergency for a complete loss of pressure.) However, with the current climate where railroaders are either thought to be incapacitated, unattentive, or incompetent, there's going to have to be a feature that acts if the engineer doesn't. Otherwise, all the electric and mechanical do-dads added are for nothing. Whether the rear portion of the train catches up with the front probably depends on conditions at the time. Also on type of train, etc. Any time I had to walk a train where we parted, there has always been a gap. However, as the cab camera video of the train derailing shows, there can be times when it happens. There are also stories about a train going into emergency at night or in the fog, the crew just finding a parted hose upon inspection. They reconnect the hose and go on their way. At the next yard they find they are a car short, or a section gang the next day finds a car in the ditch. (I 've heard the story enough to think it's a tall tale, but it probably has happened once.) Also, engines can be equipped with a 20 second delay before the PCS opens and stops the engine(s) from producing power from a train initiated emergency application. This is to allow the head end to try to pull away from the rear end. Jeff
Euclid Jeff, I see your point. It seems like both the wire and the air line parting would each tell the ECP system to set the brakes if the train parts. But even if the air line loses pressure just from a leak, surely the ECP system is going to react and do something in response.
On my carrier, most locomotives are equipped with an 'Air Flow' gauge. When the engineer observes 'air flow' in the trainline that he doesn't have a known cause for, the normal procedure is to stop the train and have the conductor inspect for a condition that is causing the air flow. Normally what is found is either a 'stretch leak' or a 'bunch leak' - these situations happen when the distance between cars changes with the change in the slack slack in the train and the air hoses move in relationship to each other and cause a short term leak in the train line - a leak that normally will not release enough air, fast enough to have the brake valves make a service application of the brakes.
Euclid [snipped - PDN] . . . I have another question. Say a loaded 100-car unit train is moving at 40-50 mph, and it breaks in two 25 cars back from the head end. Is there any tendency for the hind end cars to catch up with the head end cars after they part because all of the brakes will set up quicker on the 25 head end cars than on the 75 cars behind the break in two? It seems like the 25 cars would slow down faster than the 75 cars, but I am not sure about that.
blue streak 1 Slightly off topic is a question. Is any of the oil train product and / or pipeline going back into the strategic oil reserve ? Wasn't there a withdrawl several years ago ? Seems like a good time to " fill er up ". Naturally any Bakken or other product volitility would need to be delt with.
There was a withdrawal from the SPR in 2011, but it was not much.
http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=MCSSTUS1&f=M
Because the US produces a higher percentage of its own crude now, the SPR has lost some of its urgency. A more instructive stat is SPR Stocks as Days of Supply of Petroleum Imports.
http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=M_EPC0_VSI_NUS_DAYS&f=M
Head end also has many tons of locomotives attached to it. That adds a huge variable. Are you in power? Dynamic? Is the train bunched? Stretched? In a valley? Cresting a hill? Empties? Loads? Mixed? Where's your tonnage at? Head end? Tail? In the middle? All spread out? Are you on straight track? On a curve? Through a turnout?
There's many different scenarios. No one size fits all formula. Would be nice, but that isn't real life.
Paul_D_North_Jr So that we may properly appreciate the effects of ECP and Net Braking Ratios on train stopping distances, let's look at a few numbers (as most of you know I am wont to do - but I'll spare you the lengthy derivations): Consider a train moving at a Velocity of 40 MPH = 58.8 ft./ second - call it 60 ft./ second for simplicity, with tank cars at an average length of 60 ft. The stopping distance - ignoring reaction/ response and propagation time, which would be nil for an electronic system - and assuming the deceleration/ braking rate is essentially constant - is from basic physics: Stopping Distance = 1/2 x Braking Rate (in ft. / second, squared) x Time to Stop (in seconds), squared Knowing that the Time to Stop = Velocity / Braking Rate, and making that substitution, we get: Stopping Distance = 1/2 x Velocity (in ft. / second), squared / Braking Rate (in ft. / second, squared) Inserting the Velocity of 60 ft./ second, we start with: Stopping Distance = 1/2 x 60 ft./ second x 60 ft./ second / Braking Rate (in ft. / second, squared) Doing the multiplication, we get: Stopping Distance = 1,800 ft., squared / second, squared / Braking Rate (in ft. / second, squared) Simplifying the units, we get: Stopping Distance = 1,800 ft. / Braking Rate (in ft. / second, squared) Since Braking Rate = Net Braking Ratio x Acceleration due to Gravity ("G") = 32.2 ft./ second, squared, the number crunching will now be fairly simple. So: For an AAR S-401 2004 Minimum Braking Ratio (from the TSB report) of 11%, the Braking Rate = 11% x 32.2 = 3.54 ft. / second, squared (about 2.4 MPH per second, for those who prefer or are accustomed to seeing it expressed that way) Substituting, we get: 11% Stopping Distance = 1,800 ft. / 3.54 = 508 ft. = 8.5 car-lengths For the Maximum Braking Ratio of 14% = 4.51 ft. / second, squared (3.07 MPH/ sec.), 14% Stopping Distance = 1,800 ft. / 4.51 = 399 ft. = 6.7 car-lengths For the former standard (1999 - 2004) of 8.5% = 2.74 ft. / second, squared (1.9 MPH/ sec.), 8.5% Stopping Distance = 1,800 ft. / 2.74 = 658 ft. = 11 car-lengths If we can achieve a Net Braking Ratio of 25% with ECP brakes = 8.05 ft. / second, squared (5.5 MPH/ sec.), then - 25% Stopping Distance = 1,800 ft. / 8.05 = 224 ft. = 3.7 car-lengths So we could potentially go from pile-ups of what seem to be 10 - 20 cars - which are consistent with the stopping distances for the old 8.5% and current 11% Net Braking Ratios - to as low as 4 cars with a more powerful and faster-acting braking system. It would be interesting to compare this theoretical calculation with the performance of the subway cars that Broadway Lion refers to. If someone wants to write a R&D proposal to the FRA for this, I suppose I could be available for a modest fee . . . - Paul North.
So that we may properly appreciate the effects of ECP and Net Braking Ratios on train stopping distances, let's look at a few numbers (as most of you know I am wont to do - but I'll spare you the lengthy derivations):
Consider a train moving at a Velocity of 40 MPH = 58.8 ft./ second - call it 60 ft./ second for simplicity, with tank cars at an average length of 60 ft.
The stopping distance - ignoring reaction/ response and propagation time, which would be nil for an electronic system - and assuming the deceleration/ braking rate is essentially constant - is from basic physics:
Stopping Distance = 1/2 x Braking Rate (in ft. / second, squared) x Time to Stop (in seconds), squared
Knowing that the Time to Stop = Velocity / Braking Rate, and making that substitution, we get:
Stopping Distance = 1/2 x Velocity (in ft. / second), squared / Braking Rate (in ft. / second, squared)
Inserting the Velocity of 60 ft./ second, we start with:
Stopping Distance = 1/2 x 60 ft./ second x 60 ft./ second / Braking Rate (in ft. / second, squared)
Doing the multiplication, we get:
Stopping Distance = 1,800 ft., squared / second, squared / Braking Rate (in ft. / second, squared)
Simplifying the units, we get:
Stopping Distance = 1,800 ft. / Braking Rate (in ft. / second, squared)
Since Braking Rate = Net Braking Ratio x Acceleration due to Gravity ("G") = 32.2 ft./ second, squared, the number crunching will now be fairly simple. So:
For an AAR S-401 2004 Minimum Braking Ratio (from the TSB report) of 11%, the Braking Rate = 11% x 32.2 = 3.54 ft. / second, squared (about 2.4 MPH per second, for those who prefer or are accustomed to seeing it expressed that way)
Substituting, we get:
11% Stopping Distance = 1,800 ft. / 3.54 = 508 ft. = 8.5 car-lengths
For the Maximum Braking Ratio of 14% = 4.51 ft. / second, squared (3.07 MPH/ sec.),
14% Stopping Distance = 1,800 ft. / 4.51 = 399 ft. = 6.7 car-lengths
For the former standard (1999 - 2004) of 8.5% = 2.74 ft. / second, squared (1.9 MPH/ sec.),
8.5% Stopping Distance = 1,800 ft. / 2.74 = 658 ft. = 11 car-lengths
If we can achieve a Net Braking Ratio of 25% with ECP brakes = 8.05 ft. / second, squared (5.5 MPH/ sec.), then -
25% Stopping Distance = 1,800 ft. / 8.05 = 224 ft. = 3.7 car-lengths
So we could potentially go from pile-ups of what seem to be 10 - 20 cars - which are consistent with the stopping distances for the old 8.5% and current 11% Net Braking Ratios - to as low as 4 cars with a more powerful and faster-acting braking system.
It would be interesting to compare this theoretical calculation with the performance of the subway cars that Broadway Lion refers to.
If someone wants to write a R&D proposal to the FRA for this, I suppose I could be available for a modest fee . . .
Loaded braking force = 0.11 x 286,000 = 31,460 lbs
to 0.14 x 286,000 = 40,040 lbs.
Previous loaded braking forces were as low as 0.085 x 286,000 = 24,310 lbs with some railcars in the Lillooet report less than that.
Time to stop with ECP = speed of train /net braking ratio x gravitational acceleration = 60/(0.11 x 32.2) = 60/3.542 = 16.94 seconds
to 60/(0.14 x32.2) = 60/4.508 = 13.31 seconds.
Previous spec cars now with ECP could take 60/(0.085 x 32.2) = 60/2.737 = 21.92 seconds.
Let us also take a look at empty unit trains.
Empty braking force = 0.15 x 60,000 = 9,000 lbs
to 0.32 x 60,000 = 19,200 lbs.
Previous spec cars could have up to 0.38 x 60,000 = 22,800 lbs.
Time to stop with ECP = 60/(0.15 x 32.2) = 60/4.83 = 12.42 seconds
to 60/(0.32 x 32.2) = 60/10.24 = 5.86 seconds.
Previous spec cars now with ECP could stop as quick as = 60/(0.38 x 32.2) = 60/12.236 = 4.90 seconds. Remember the limitations on Paul's analysis.
One of Paul's articles said that without ECP it takes 100 seconds for the brakes to activate on the 100th car, but I would prefer to see the results of an FRA test. If a separation occurs after the 25th car, the front 25 cars will stop before the last 75. Car 26 with 11% braking ratio is still being pushed at 16.94 seconds with 16 cars braking and 59 cars waiting for the word.
Euclid oltmannd Euclid According to the FRA final report on ECP brakes for freight service, August 2009, ECP brakes reduce the stopping distance to 40 to 60% of the stopping distance with conventional air brakes. They cite a test of a loaded 100-car train moving at 50 mph. With conventional air brakes, the train took 4,100 feet to stop. With ECP brakes it took 2,500 feet to stop. A shorter stopping distance means that the cars behind a derailment and developing pileup will lose their kinetic energy sooner; and will therefore shove fewer cars into the pileup. Identical braking ratio on the cars? I doubt it. ECP doesn't develop more braking force in and of itself. I never said that it develops more braking force. It stops the train quicker because it takes less time to apply the brakes.
But, you don't know about the particulars in the test...
Euclid It seems like both the wire and the air line parting would each tell the ECP system to set the brakes if the train parts.
You wouldn't want to a loss of comm/wire parting to be set at an absolute level. You are never going to have a "pure" electric trainline and comm is going to be dirty quite often. You don't want to dump the air every time you get an invalid comm data packet, or a zero voltage blip.
This isn't a LAN connection from your modem to your computer. This is 200+ wire connectors in series, in dirty environment -both physically and electrically.
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