Jim200 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. Lets continue with Paul's analysis of a train going 60 ft/sec,(40.9 mph), and look at car braking forces and time to stop by considering an empty weight of 60,000 lbs and fully loaded weight of 286,000 lbs, and having an empty/load device. The net braking ratio is the car braking force divided by the weight,(or ma/mg = a/g), which AAR S-401 specs in 2004 required 11% to 14% for a loaded car and 15% to 32% for an empty car. The previous 1999 spec was 8.5% to 13% for loaded and a maximum of 38% for an empty car. 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.
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 . . .
- Paul North.
Lets continue with Paul's analysis of a train going 60 ft/sec,(40.9 mph), and look at car braking forces and time to stop by considering an empty weight of 60,000 lbs and fully loaded weight of 286,000 lbs, and having an empty/load device. The net braking ratio is the car braking force divided by the weight,(or ma/mg = a/g), which AAR S-401 specs in 2004 required 11% to 14% for a loaded car and 15% to 32% for an empty car. The previous 1999 spec was 8.5% to 13% for loaded and a maximum of 38% for an empty car.
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.
The braking signal propogates down the train line at nearly the speed of sound. The delay from the arrival of the signal to the brake shoes hitting the wheels, to full braking pressure being applied is caused primarily by the damping in the brake valves to keep them stable (so the don't tip over into emergency when all you want is a controlled service application) and by friction working itself out of the brake rigging. ECP will help with the former but not the latter.
If you derail a train, you have significantly higher deceleration occurring at the point of the derailment - to the point it may not matter much if you have 11% braking ratio or 25% braking ratio - and ECP or plain-jane ABDW brake valves.
Does it really matter much if you apply the brakes in your car as it hits a wall?
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
oltmannd 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 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.
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.
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 Here is international consulting group, Oliver Wyman echoing my ideas. Note that they have not yet gotten to my idea of differential braking as the ultimate safety enhancement. http://blogs.oliverwyman.com/rail/wp-content/uploads/sites/4/2014/07/Crude-By-Rail-Collaboration-POV-Final.pdf Quotes from Oliver Wyman, see pages 5-6: “With so many new cars being introduced onto the rail network, and given that most crude oil is being targeted for unit train operations, this may raise opportunities for step changes in fleet safety and performance. 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. This would enable braking to be applied faster and more consistently in a unit train in the event of an incident…” “With electronic train lines from ECP braking systems, it might also make sense to equip the trucks on tank cars with sensors that could detect the kind of rough sudden motion that indicates a derailed wheel set and immediately apply the brakes on the train. Seconds count in a derailment event, and this would stop a train far more quickly than waiting for the derailment to progress to the point that the train line was severed…”
All of this may be possible, and desirable. I believe ECP braking is desirable for these, and many other reasons. I believe the industry is a bit slow coming to the ECP party, too.
But, not for even a second, do I think a viable, tested and ready, ECP system currently exists. Sure, there are test trains out there - but they are in captive service. Getting from the current state of the art to a fully deployable system is not simple nor an easy task. Even when plain-jane ECP is ready to deploy, adding in all the "bells and whistles" that it will allow are a whole, 'nother thing again. Doable, but not trivial.
As evidence, take a look at hot box detectors. How long have they been around? Decades. Their biggest problem? False positives. Much better than 20 years ago, but still not zero. False positives are capacity killers. You can't tolerate an advanced ECP system with false postive train stops all over the place.
Can an advanced ECP system reliably replace the current system? Sure. But, it won't be easy or quick. Mandating it on oil trains - even in it's simple form - isn't helpful.
Apparently, a disconnected cable could trigger an ECP emergency. From WABTEC catalog (http://www.wabtec.com/railroad/WabtecFreightCatalog.pdf)
Intercar Cable The ECP Inter-Car Cable and Lanyard is used to connect the 230VDC Trainline between ECP wagons and locomotives. The cable complies with the S-4210 Standard and has been approved by the AAR for use on S-4200 compliant ECP trains. The connector end is designed to allow the cars and locomotives to be easily connected and disconnected. When in operation, the cable and lanyard lengths are specified to pull apart prior to the brake pipe separating to initiate an ECP Emergency
To my knowledge, there has yet to be established a industry wide standard for ECP. At present there are several competing designs for ECP. Until the industry defines a standard for all manufacturers to build their equipment to, there will never be any ECP outside of a test enviornment.
Never too old to have a happy childhood!
I agree that ECP needs more development to arrive at a standard system for application. I expect that an ECP mandate for oil trains will include a substantial phase-in period.
EuclidSo it raises again the question of applying ECP only to dedicated trains.
I understand what you are saying, but just applying ECP to oil trains is quite a bit more logistically difficult than it may seem.
Do the train sets stay in the same lanes? Not as much as one would hope.
Is it practial to keep equipped locomotives with the train sets? No. You'd need a good fraction of the fleet equipped to cover oil trains.
How do I handle cars entering and exiting unit train service? How do they move?
How many mechanical folk need to be trained to handle ECP? Nearly all.
How many places to I have to keep the electrical jumpers? Spare brake valves, etc. Everywhere.
How do I move disabled trains?
How do I cover trains that need RR specific cab signalling as a leader?
etc. etc.
I'm not saying it isn't a good idea to move toward ECP. I just believe it's ability to reduce risk on oil trains is not worth the overall risk and cost to the network. It would be a bad idea to mandate it.
Euclid DERAILMENT SENSORS The point of my 100-car train derailing at the 25th car example is just to isolate the effect of the propagation time of an emergency application with conventional air brakes. I conclude that it does fundamentally result in relatively high compression force between cars 25 and 26. I agree that there are many variables that will affect this outcome, but I am just looking at the basic effect in isolation. Also entering into this effect is the fact that most mid-train derailments occur near the head end. This gets back to derailment sensors. As we have seen, several foreign railroads use mechanical derailment sensors on trains with conventional air brakes. They sense a derailment at a specific car, and initiate an emergency application from that car. The objective is to begin braking to get the train stopped as soon as possible; as opposed to just waiting for the train to part as a response to the derailment, and thus causing an emergency application. The problem that I see is that the dynamiting of the train brakes caused by the command of the derailment sensor is quite likely to cause excessive buff or compression force to jackknife the derailed car before it would have begun jackknifing without derailment sensors. In fact, without the preemptive action of derailment sensors, the car may never have jackknifed. In other words, derailment sensors could cause pileups that would not happen without them. Just the fact that the car is already derailed means that it is more easily jackknifed because it has lost some of its guidance. Therefore, I conclude that the mechanical derailment sensors on a train with conventional air brakes is a flawed concept. On the contrary, this destructive effect of derailment sensors is completely eliminated if they are applied to a train with ECP brakes. This is because the simultaneous application of ECP brakes does not produce the excessive buff force in derailments near the head end.
You are pretty much assuming derailments are caused by a wheel hopping over a rail. There are also:
Broken wheels.
Broken axles.
Failed axle bearings.
Each of these are going to result in different dyanmics. In many cases, some part of the car will "dig in" to the ROW and no amount of braking will stop the pile-up.
What about putting the following on the FRED - right now, transmits to the cab, so no upgrade of any cars required:
Paul_D_North_Jr What about putting the following on the FRED - right now, transmits to the cab, so no upgrade of any cars required: Derailment sensor Video camera view to the rear, to be able to check for track damage, etc. if a derailment (or leak, etc.) is suspected. - Paul North.
oltmannd Euclid So it raises again the question of applying ECP only to dedicated trains. I understand what you are saying, but just applying ECP to oil trains is quite a bit more logistically difficult than it may seem. Do the train sets stay in the same lanes? Not as much as one would hope. Is it practial to keep equipped locomotives with the train sets? No. You'd need a good fraction of the fleet equipped to cover oil trains. How do I handle cars entering and exiting unit train service? How do they move? How many mechanical folk need to be trained to handle ECP? Nearly all. How many places to I have to keep the electrical jumpers? Spare brake valves, etc. Everywhere. How do I move disabled trains? How do I cover trains that need RR specific cab signalling as a leader? etc. etc. I'm not saying it isn't a good idea to move toward ECP. I just believe it's ability to reduce risk on oil trains is not worth the overall risk and cost to the network. It would be a bad idea to mandate it.
Euclid So it raises again the question of applying ECP only to dedicated trains.
The way I understand it, for the forseeable future ECP cars will be equipped to operate either in ECP or conventionally. A car could move in unit train service in ECP mode or in general service with conventional air brakes. (A lot more flexible than specialized couplers.)
I think some cars, like covered or open hoppers, that can find themselves in either unit train or general service are being manufactured with some ECP compatible components. They aren't fully equipped, but will be easier to equip if ECP is adopted.
Jeff
Euclid Here is a great illustration of the effect of my proposal for differential braking that I have previously described. Refer to this video: https://www.youtube.com/watch?v=j8kONLIWlBs The point of my differential braking proposal is to stretch the train ahead of the derailment for the purpose of preventing the cars from jackknifing and starting the pileup process.
Critics might say that nothing can prevent the jackknifing once the cars derail because total chaos will ensue and the cars will go every which way as they jam their trucks, tear up the track, and break their couplings.
Yet this video shows that eight cars ahead of the pileup were dragged, thus keeping them in line and on the track bed. The derailed car furthest from the pileup was the first to derail back where the pileup ultimately occurred. When it derailed, it began tearing up the track, causing the next car behind it to derail. The cars derailed in succession as they arrived at the track damage until eight cars were derailed and were being dragged forward. As those eight cars dragged, they destroyed the track, and tore their trucks off.
Yet, they stayed coupled together, in line, and generally upright. They were being dragged by the kinetic energy of the cars ahead of them and/or by the continued pull of the engine. They surely would have jackknifed if they were not being pulled ahead.
Dave H. Painted side goes up. My website : wnbranch.com
dehusman Euclid Here is a great illustration of the effect of my proposal for differential braking that I have previously described. Refer to this video: https://www.youtube.com/watch?v=j8kONLIWlBs The point of my differential braking proposal is to stretch the train ahead of the derailment for the purpose of preventing the cars from jackknifing and starting the pileup process. And I don't see how this illustrates the advantage of your "differential braking". The head end WAS STRETCHED. The cars still derailed, the cars still left the track structure, the derailed cars slowed faster than either the head end or the rear end, the cars jacknifed, the rear of the train ran into the derailed cars. Critics might say that nothing can prevent the jackknifing once the cars derail because total chaos will ensue and the cars will go every which way as they jam their trucks, tear up the track, and break their couplings. Critics or any reasonable person who looks at the video. The cars did derail. They did tear up the track. the trucks and cars did dig into the roadbed, the cars did jacknife, they did go in different directions, they did break their couplings. It all happened just the way it has ben said it happens. Facts. Visual evidence. Yet this video shows that eight cars ahead of the pileup were dragged, thus keeping them in line and on the track bed. The derailed car furthest from the pileup was the first to derail back where the pileup ultimately occurred. When it derailed, it began tearing up the track, causing the next car behind it to derail. The cars derailed in succession as they arrived at the track damage until eight cars were derailed and were being dragged forward. As those eight cars dragged, they destroyed the track, and tore their trucks off. Exactly and so how is doing this intentionally supposed to STOP trains from jacknifing, pileing up and causing a release since they did stretch the head end and the train STILL jacknifed, piled up and caused a release. If anything this is a perfect example of why differential braking doesn't work. All the stuff you say differential braking is supposed to prevent still happened. Yet, they stayed coupled together, in line, and generally upright. They were being dragged by the kinetic energy of the cars ahead of them and/or by the continued pull of the engine. They surely would have jackknifed if they were not being pulled ahead. Yeah the head end cars did, the did you notice the jacknifed pile of smouldering cars behind the head end cars.
jeffhergertThe way I understand it, for the forseeable future ECP cars will be equipped to operate either in ECP or conventionally. A car could move in unit train service in ECP mode or in general service with conventional air brakes. (A lot more flexible than specialized couplers.) I think some cars, like covered or open hoppers, that can find themselves in either unit train or general service are being manufactured with some ECP compatible components. They aren't fully equipped, but will be easier to equip if ECP is adopted. Jeff
Going the "dual - equipped" route is a tough one. Really adds to the cost. But, the path forward for "loose car" ECP sure is foggy.
I'd guess the "pre-equipping" is having a manifold that an ECP brake valve can bolt up to.
We are a long ways away from having a reliable, ECP system that could be applied fleet-wide. We don't even have reasonable implemention path.
I find discussing all the "what-else?" features that could be added to ECP, like derailment avoidance and mitigation interesting, but really too far "out there" to be of any practical value solving exisitng problems with oil trains.
Before there is operative ECP - there must be a AAR defined standard for ECP. To date there is none. Without a industry wide standard ECP is just a toy to be experimented with.
Electronics, differential brakes, load/MTY electrono sensors, etc....
Way too many components that will need proper maintenace to function properly. Sorry, but that doesn't give me a warm and fuzzy feeling. Not all brakes are created equal. Trying to add more electronics to that seems a lesson in futility. Sometimes you can have a train and throw 10lbs and it grinds to a stop (damnit. Hold on conductor, I have to release and start again!). Other times, you may have a similar train and need 15-20#s before it grabs (c'mon... any day now!)
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
zugmann Electronics, differential brakes, load/MTY electrono sensors, etc.... Way too many components that will need proper maintenace to function properly. Sorry, but that doesn't give me a warm and fuzzy feeling. Not all brakes are created equal. Trying to add more electronics to that seems a lesson in futility. Sometimes you can have a train and throw 10lbs and it grinds to a stop (damnit. Hold on conductor, I have to release and start again!). Other times, you may have a similar train and need 15-20#s before it grabs (c'mon... any day now!)
One poster here thinks it's the only answer and no one can change his mind.
Norm
Railway Age expands upon the NTSB's Good Friday present.
http://www.railwayage.com/index.php/regulatory/ntsb-wants-all-tanks-in-a-blanket.html?channel=40
Norm48327 zugmann Electronics, differential brakes, load/MTY electrono sensors, etc.... Way too many components that will need proper maintenace to function properly. Sorry, but that doesn't give me a warm and fuzzy feeling. Not all brakes are created equal. Trying to add more electronics to that seems a lesson in futility. Sometimes you can have a train and throw 10lbs and it grinds to a stop (damnit. Hold on conductor, I have to release and start again!). Other times, you may have a similar train and need 15-20#s before it grabs (c'mon... any day now!) One poster here thinks it's the only answer and no one can change his mind.
1) ECP brakes
2) Empty/loaded sensors
3) Derailment sensors
4) Differential ECP braking
EuclidEach one of these would add to the solution. Of those four, only #4 is my idea. The first three are under development have proven merit. They all cost money, but so does losing the oil business.
The oil business will be lost when it is too expensive to extract/ship (kind of happening now anyhow). Forcing these additions will just hasten the process.
EP-60 from New York Air Brake.
http://www.nyab.com/en/products/ep60/featuresbenefits/featuresbenefits_10.jsp
The link below goes to the page before the one above. It has a pdf of the brochure, which has a diagram of where the parts go.
http://www.nyab.com/en/products/ep60/ep60_1.jsp
Now please don't think I'm endorsing Euclid's ideas about oil trains. Or that I think the railroads should be required to use ECP. I do think that given the choice between PTC or ECP, I would rather have seen the adoption of ECP. I think it would deliver more benefit than PTC.
jeffhergert I do think that given the choice between PTC or ECP, I would rather have seen the adoption of ECP. I think it would deliver more benefit than PTC.
Given an either/or... I agree. But, both together are more than the sum of the parts. For perspective, the $10.2B NS and CSX paid for CR could have equipped the entire NA frt car fleet with ECP at $10k/car.
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