I understand there are FREDS in use on some railroads that do operate as remote control brake controllers, and that is the type that would be modified to attach to two air hoses instead of just one. Obviously the idea has to tested on a test train. The tests would determine how many cars can be located between devices without loosing the electronic brake advantage. But obviouly such a device is a lot less expensive than just adding midtrain power for braking control. The good feature is no modification of the existing fleet is required. And generally a portable device that is hung on a grab iron is less expensive than the same device installed pementanly on the car.
And there is no reason why such a device could not be comopatible with installed devices, although obviously wire-controlled devices instead of radio controlled would require that electronic-brake cars either be bunched at the head end or controlled by a separate portable radio-contolled device. It might turn out to be only an interem soluton, but still one worth considering and testing.
Euclid In either case, the improved stopping power is relatively modest, and not likely to produce the safety enhancement effects that the Secretary of Transportation cites in the quotes above.
And how many replies and time required to write them for this conclusion to be finally be reached?
zugmann Euclid But that is not what the USDOT is concerned about in their mandate for ECP on oil trains. Their concern has nothing to do with service braking applications and everything to do with emergency application. Sounds like the USDOT has absolutely no clue about train brakes at all. But hey, let's insert more gadgets! That'll work. Oh well. We'll make do with whatever gets thrown down the pipeline. That's what we do. Then the people in charge can pat themselves on the back for doing a great job.
Euclid But that is not what the USDOT is concerned about in their mandate for ECP on oil trains. Their concern has nothing to do with service braking applications and everything to do with emergency application.
Sounds like the USDOT has absolutely no clue about train brakes at all. But hey, let's insert more gadgets! That'll work.
Oh well. We'll make do with whatever gets thrown down the pipeline. That's what we do. Then the people in charge can pat themselves on the back for doing a great job.
Johnny
Euclid Dave, They are concerned with mitigating the pileup by reducing stopping distance. Secretary of Transportation, Anthony Foxx said this as paraphrased by the article I linked above: Foxx maintained that the [ECP] brakes could prevent a repeat of incidents like a December 2013 collision in which an oil train slammed into a derailed grain train, setting off a series of explosions outside Casselton, N.D. He was referring to ECP brakes reducing stopping distance. His point was that quicker stopping offered by ECP might have stopped the oil train before it collided with the fouling grain train in the Casselton wreck. He also said this as quoted by the article I linked above: “ECP brakes can reduce how long it takes a train to stop,” Foxx said. “They can prevent cars from slamming into each other, they can decrease the number of cars that derail, they can greatly reduce the probability that tank cars will puncture. This is proven technology.” He was referring to the superior stopping power of ECP helping to mitigate the damage in a derailment after the derailment begins. The point that you make about additional FREDS reducing stopping distance equivalent to ECP is essentially the same point being made by the railroads as they oppose the ECP mandate. But the railroads say this is already being accomplished by distributed power creating more holes in the brake pipe during an emergency application. But, as I understand it, this improved stopping performance is very small no matter whether it comes from ECP compared to Westinghouse; or whether it comes from distributed power on Westinghouse compared to Westinghouse without distributed power. In either case, the improved stopping power is relatively modest, and not likely to produce the safety enhancement effects that the Secretary of Transportation cites in the quotes above.
Has Foxx stated what the sight line was to the derailing car(s) of the grain train as the oil train approached? When trains meet or pass each other, the sight lines in many cases are severely restricted by curvature (and the curves themselves do not have to be severe). Just like life, one second everything is fine, the next catastrophy.
Any engineer that would use any form of Service brake application upon viewing an approaching derailment situation, won't maintain his engineers certification very long.
Never too old to have a happy childhood!
Ok, so it might stop a little quicker, but the focus? Stopping 500 yards quicker does not solve jumping the tracks... And, that 1-1/2 miles, minus 500 yards (speculation on how much shorter.) would not be helpful if, as in the collision of two trains in N.D. mentioned above, the sight line was only 1000 yards away... ECP maybe helpful in some conditions, but is not the miracle cure the opponents of this traffic want.
The focus should start on preventing derailments, and preventing the exploding crude. Sure, help with stopping distance, but focus on the real problems, the crude itself being volatile, and the leaving the tracks.
And, no, it will not prevent all issues. Nothing will prevent every single derailment from occurring. They will still occur when things go wrong, nothing will change this. Can it be made safer? Yes. "Bullet proof" and "idiot proof"? No. So, even with ECP, safer tank cars, better track work, etc... will not bring the miracle cure that people want. It just will not, and cannot, happen the way everyone wants.
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
Buslist Euclid In either case, the improved stopping power is relatively modest, and not likely to produce the safety enhancement effects that the Secretary of Transportation cites in the quotes above. And how many replies and time required to write them for this conclusion to be finally be reached?
wanswheel, quoting the FRA"The availability of graduated release will permit greater reliance on dynamic braking in mountain grade territory, reducing thermal inputs to wheels."
Want to bet that this opinion has changed somewhat following the 17 Mile Grade 'incidents'?
Euclid Buslist Euclid In either case, the improved stopping power is relatively modest, and not likely to produce the safety enhancement effects that the Secretary of Transportation cites in the quotes above. And how many replies and time required to write them for this conclusion to be finally be reached? The conclusion is still pending final review before I will accept it. If the conclusion is correct, then the USDOT is wrong. They have promised to have one of their technical experts call me to answer my questions. For the time being, the conclusion is that the stopping distance for Westinghouse brakes is very close to being equal to the stopping distance for ECP with both in the emergency application. Yet I know I have seen a reference somewhere recently that mentioned flow restrictors affecting the emergency application as well as the service application of Westinghouse brakes. Here is a reference to Westinghouse stopping distance: http://www.tarorigin.com/art/Jbentley/ It claims that for the Westinghouse brakes to fully apply on a 5,526-ft. long freight train, it takes 16 seconds. The larger part of that (ten seconds) is the time required for the air to flow from the reservoir to the brake cylinder on each car. So, according to that, it is not true that the only factor affecting stopping distance is the sequential propagation time for Westinghouse brakes. Obviously the railroads do not want to spend the money to comply with the ECP mandate, so I take their claims about braking performance with a grain of salt. It may be that the railroads are downplaying the stopping performance of ECP in the emergency braking application, and exaggerating the stopping performance offered by distributed power in the emergency braking application. Likewise, the ECP manufacturers have a great stake in exaggerating ECP advantages. Their agenda may indeed be sufficient to bamboozle the USDOT.
Please read your reference more carefully! It states that the FRA requires full brake pressure in less than 10 seconds, NOT that 10 seconds is required. So the 16 seconds is a worst case situation. It also says that emergency braking "applies the brakes as quickly as possible " . Note this guy is a plaintiff's expert witness trying to get $ from the railroads in grade crossing incidents. Biased?
BuslistPlease read your reference more carefully! It states that the FRA requires full brake pressure in less than 10 seconds, NOT that 10 seconds is required. So the 16 seconds is a worst case situation. It also says that emergency braking "applies the brakes as quickly as possible " . Note this guy is a plaintiff's expert witness trying to get $ from the railroads in grade crossing incidents. Biased?
Perhaps I might quote directly from the reference:
"The Federal Railroad Administration, under CFR Part 49, specifies the maximum time each car can take to achieve maximum braking. On trains operating at 70psi brakepipe pressure this maximum application time is 10 seconds. So, our hypothetical 5,526' freight train would take 16 seconds to attain full emergency braking. During this 16 seconds the train will have steadily increasing brake application taking effect between 1.5 (the time for braking in the first car to begin) to 16 seconds (the time the last car achieve full braking)"
I think this is adequately clear for anyone to comprehend. What might help would be a graph of deceleration (or actual braking effort) against time, showing the rate of change of deceleration first as the brakes are set up to engage, and then as they progressively come on.
I, for one, found the analysis he provided of the hypothetical grade-crossing collision highly interesting, as both his explanation and the resulting 'numbers' have a bearing on the present "discussion". Note that if I understand what he has said correctly, the difference between putting the train in emergency and NOT APPLYING THE BRAKES AT ALL translates into barely more than half a second's time at the hypothetical point of impact, more than half the way to the calculated point the train will come to a complete stop.
Much as I may hate to say it, I found the explanations of brake-system operation and train dynamics to be objectively correct and well-worded, and I saw only one instance of potential 'bias' (where he said that the .57 seconds might have allowed one more car to get across the crossing before the train would hit it...)
WizlishOn trains operating at 70psi brakepipe pressure this maximum application time is 10 seconds.
Given that most railroads operate on a brake pipe pressure of 90 PSI, these numbers would likely be inaccurate.
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...
90 psi is at the engine, the 70 psi assumes "normal" trainline leakage.
With conventional power the gradient is a straight slope front to back, with DPU it slopes from either end and is lowest at the furthest point from the engines (depending on where they are in the train). Times and pressures higher than 70 psi will yield better results.
Dave H. Painted side goes up. My website : wnbranch.com
dehusman 90 psi is at the engine, the 70 psi assumes "normal" trainline leakage. With conventional power the gradient is a straight slope front to back, with DPU it slopes from either end and is lowest at the furthest point from the engines (depending on where they are in the train). Times and pressures higher than 70 psi will yield better results.
If the head end is charged to 90 and the rear end only reads 70 - the Conductor is going to expend shoe leather looking for the leaks.
Let's throw something else into the mix. A DPU can initiate service and emergency braking from the rear of the train. The EOT device can initiate emergency braking from the rear of the train. Could not an EOT be equipped to also initiate a service brake application from the rear?
Seems that might negate the need for a lot of expensive equipment on each car and would reduce the stopping distance. It would require radio communication from the locomotive but surely would be less costly than ECP.
Just a thought.
Norm
http://www.cbsnews.com/news/north-dakota-town-evacuated-after-oil-train-derailment/
No comment necessary.
C&NW, CA&E, MILW, CGW and IC fan
ECP does not have "zero" propagation time, and engineers and government people alike will laugh at your state of knowledge if you say that. There is a finite time for the valve to open and establish flow once it is energized, and then a lag before pressure becomes sufficient at the brake cylinders to take the slack out of the linkage and bring the shoes into contact with the wheels. This is unavoidable delay in any foundation-braked system that is not equipped with, say, some whackjob version of pyrotechnic devlces like seat-belt tensioners that eliminate all slack and lost motion quickly -- and even in that case there wouldn't be "zero" reaction or activation time.
Your 'transfer time' is something that's already been partially answered: the rate of transfer can be, and almost always is, quicker (it can be MUCH quicker) on a proper ECP system than for pneumatic control.
One very important reason why this can be done is the existence of graduated release on a proper ECP system. If the rate of brake application is too high, the ECP valves can be modulated to control the 'transfer' rate, and even if the brake application force has 'overshot' in the interval, the situation can be corrected (and proper braking profile restored) in no more than seconds. With the triple system, the only way to relieve the situation is to spill the brakes and wait for the line to recharge sufficiently to reapply -- not something likely to happen effectively, in a number of regards, during an 'emergency' application.
Buslist: surely there are terms in current ECP practice that distinguish the setup time from the actual brake-application time. Can we determine what thos are, and then use them instead of Euclid's made-up terms in the technical discussion going forward?
EuclidIs there any difference in transfer time between ECP and conventional air brakes?
Some, but not much. Air brake valves have some amount of damping and throttling built in to keep the valve response stable. Much less is need if you are going to just pop open a magnet (solenoid) valve. There is still a bit of time to get the brake rigging to settle out and get the full force against the wheels.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
schlimm http://www.cbsnews.com/news/north-dakota-town-evacuated-after-oil-train-derailment/ No comment necessary.
Residents have returned to homes. Noteworthy is the fact that the oil in the shipment had been treated by Hess to reduce volatility, yet the six derailed cars still exploded, although probably less in scale compared to those at Lac Magentic. Wheel problems (as at Galena) seem to be the focus of the investigation.
http://www.sunherald.com/2015/05/07/6214911/evacuated-residents-allowed-home.html
CMStPnPI kind of like what I perceive is the BNSF strategy evolving here. Ask the FRA for permission to deny carrying some hazardous cargoes as a Common Carrier. Once permission is received setup your own specs for handling this cargo OR charge a premium for hauling it using the newly gained right of refusal.
I want to bump this thought up, considering I am becoming aware of a growing number of voices that say oil trains CAN'T be effectively made 'safe enough' strictly through technical 'improvements' like a few 16ths added shell thickness, 'rollover protection', or ECP-that-doesn't-help-in-many-situations.
The most logical conclusion, I think, is to extend the kind of provisions airlines (and FedEx et al.) already enjoy: they don't take explosives, oxidizers, and a wide range of other hazardous cargoes, and are not required by the Government to do so. The justification is that unavoidable hazard (to aircraft in flight) is posed by these. That is no different from the evolving consensus on oil fireballs following accidents such as derailments. It really is no different from toxic release or damage following breached PIH-carying cars following accidents such as derailments.
I can easily see a political consensus building around giving railroads the authority to refuse 'automatic' carriage of HHFT or PIH traffic, and demand either a surcharge or additional 'named insured' coverage on specific policies to handle any such traffic. If there is additional cost, expense, or inconvenience on railroads for the special train arrangements the Government now proposes for oil trains, it should be borne entirely by shippers, should be borne up front or in advance, and should include some factor for the 'consequential damage' to other traffic, specifically including Amtrak, that is delayed or inconvenienced by at least that proportion of oil-train handling troubles that result from Government mandates.
(I just can't resist adapting the old advertising-agency chestnut:
HHFT-tIH, tha-tha, tha-tha-that's all, folks!)
Yes it will explode. If a car was filled with water and immersed in a fire, the car of water would explode. That's why the new standards call for thermal jackets on the cars. That extends the time to heat the contents (raising the internal pressure) from dozens of minutes to dozens of hours.
Still if you look at the derailment, the major risks are from fire, (most of that is the areas downhill of the site, the fire spreads not by "explosion" but by liquid commodity flowing downhill) and from pollution (air and water).
For all the comments about "explosions", the damage in this (and every other oil train derailment) only extends a hundred yards or so from the derailment, except in the areas downhill from the site where the burning liquid oil flows. If you contrast that with West, TX, a true explosion, there was structural damage to buildings a quarter mile away. At West, about 400 tons of product went up. In this derailment about 600 tons and at Lac Megantic 4000 tons. In all the oil train derailments the damage was confined to an area a hundred yards or so from the derailment, except where the burning product flowed away from the site.
WizlishECP does not have "zero" propagation time, and engineers and government people alike will laugh at your state of knowledge if you say that. There is a finite time for the valve to open and establish flow once it is energized, and then a lag before pressure becomes sufficient at the brake cylinders to take the slack out of the linkage and bring the shoes into contact with the wheels. This is unavoidable delay in any foundation-braked system... ...there wouldn't be "zero" reaction or activation time.
Wizlish CMStPnP: I kind of like what I perceive is the BNSF strategy evolving here. Ask the FRA for permission to deny carrying some hazardous cargoes as a Common Carrier. Once permission is received setup your own specs for handling this cargo OR charge a premium for hauling it using the newly gained right of refusal.
Wizlish: I want to bump this thought up, considering I am becoming aware of a growing number of voices that say oil trains CAN'T be effectively made 'safe enough' strictly through technical 'improvements' like a few 16ths added shell thickness, 'rollover protection', or ECP-that-doesn't-help-in-many-situations. The most logical conclusion, I think, is to extend the kind of provisions airlines (and FedEx et al.) already enjoy: they don't take explosives, oxidizers, and a wide range of other hazardous cargoes, and are not required by the Government to do so. The justification is that unavoidable hazard (to aircraft in flight) is posed by these. That is no different from the evolving consensus on oil fireballs following accidents such as derailments. It really is no different from toxic release or damage following breached PIH-carying cars following accidents such as derailments. I can easily see a political consensus building around giving railroads the authority to refuse 'automatic' carriage of HHFT or PIH traffic, and demand either a surcharge or additional 'named insured' coverage on specific policies to handle any such traffic. [/quote]
BNSF may be using a new strategy or may be only posturing. I wonder how many railroads would refuse to carry hazardous shipments if they actually had the authority to do so? Making money is an attractive lure.
WizlishBuslist: surely there are terms in current ECP practice that distinguish the setup time from the actual brake-application time. Can we determine what thos are, and then use them instead of Euclid's made-up terms in the technical discussion going forward?
One thing I am curious about is have the derailed cars had breeches to their walls or have the appliances (valves, and covers) been the source of the oil spilled in the derailment? I know the 117 cars are supposed to have skids or something to protect the underside valve. Obviously when a car derails, there are excess forces on any and everything. So are the cars splitting at a weld, being punctured or how have they failed? Are they rupturing do to heat created by the fire after the derailment and the fire is from oil that has come out of what opening. This is not clear to me.
EuclidI will bet you cannot find standard industry terms that match the definition of the terms that I have made-up.
No question you have me there!
EuclidAll that I am trying to do is get to some degree of clarity in the difference between the stopping distance and time between ECP and conventional air brakes. I make up terms and then define them just for that purpose of getting clarity.
If that is your purpose, you are either failing dramatically or have a definition of 'clarity' that matches ex-President Clinton's take on 'truth'.
I was trying to establish that there are several different actions that characterize a brake application. You seem to be going back to your terminology that does not account for what real brakes do in realtime, and then start to get ugly or snide when that terminology is questioned.
By all means, keep using your terms, and keep obfuscating. That will give real engineers time to study and develop effective models of what ECP braking actually does or doesn't do, relative to conventional brakes, and then refine whatever systems presently exist to see how they can be optimized.
Electroliner 1935 One thing I am curious about is have the derailed cars had breeches to their walls or have the appliances (valves, and covers) been the source of the oil spilled in the derailment? I know the 117 cars are supposed to have skids or something to protect the underside valve. Obviously when a car derails, there are excess forces on any and everything. So are the cars splitting at a weld, being punctured or how have they failed? Are they rupturing do to heat created by the fire after the derailment and the fire is from oil that has come out of what opening. This is not clear to me.
As I recall from the Canadian TSB report on the northern Ontario CBR fires this past winter, they said that some of the wrecked cars leaked oil, and subsequent pool fires cooked other tank cars until they ruptured and exploded. They had pictures of large tears where the tank walls had bulged.
EuclidBut let’s back up and let me ask the question this way, pertaining only to an emergency application of brakes of a 5,526-ft. long train, using Westinghouse brakes compared to ECP brakes ...
If I might suggest: we need to use a train composed of a certain number of cars, each of a certain weight, and only circumstantially (for Westinghouse) determine the brake-pipe length from the car data.. I was thinking we should use 'common oil-train parameters' here, rather than the reference example. I am preparing a 'call for graphics' that will, I hope, clarify a great many things about this.
... The electronic brake initiation signal of ECP travels the length of the train at the speed of light, and the pneumatic signal of Westinghouse brakes travels the same distance in 6 seconds. So we know that ECP will stop the train at least 6 seconds sooner than Westinghouse.
We know no such thing! That would be the case if NO brake on the Westinghouse train started to apply until the signal had propagated to the end of the trainline. You can readily see how silly an assumption that would be. The Westinghouse will be 'lagging' a bit more in actuation at each successive car, so the deceleration force exerted by the train will begin to lag progressively behind the ECP response, but the time of valve actuation at the first few cars is virtually identical. (I won't yet consider if the respective valves open at different speeds or to different openings) You can approximate the braking response curve by plotting where the brake valves are located along the virtual length of the trainline, determining when the idealized pressure pulse reaches each, and then summing the responses appropriately.
Now, I consider the differential 'transfer time' (to use your term here in the sense I think you mean it) to be a much more significant contributor to rapid ECP braking than propagation is. As Buslist and others have noted, ECP can have much more robust flow through the valve and transfer piping to establish and ramp up pressure in the brake cylinders. In part this is a consequence of the rapid coordinated brake-valve response characteristic of ECP; in part it is made workable by the ECP ability to perform gradiated release if the fast brake-valve response overshoots or is otherwise determined to be excessive. Typical freight Westinghouse is required to have a slower response time than a typical ECP valve.
Now it seems to me that since the slower return time is built into the triple valve, you'd see a pronounced difference in the braking performance aside from that provided by the electronic valves. For there to be the minimal difference observed between ECP and Westinghouse in the reported testing, there almost has to be some sort of 'accelerating valve' that can apply full pressure to the brake cylinder... that is in many cases a bad thing.
Is there any other factor with either brake system that makes a difference in stopping time and distance? If so, what is that factor, and what difference does it make?
There are several, and more are possible in more complex or sophisticated ECP systems (individual-axle wheelslide protection, for example). I will introduce a couple when I get done with a proposal for an analytic framework for this issue. Bear with me till then.
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