The semi-permanently coupled car idea actually dates at least back to 1998, when UP started running trains between the San Ardo oil field and Wilmington. Per the sidebar in the March 2014 issue of trains:
...the train, which consist of 78 tank cars, in six strings of 13 semi-permanently connected groups.
But... This is a very specific move of about 300 miles, between places set up to handle the consist. It's also running in California, with little chance of the weather the northern tier trains will encounter 3-4 months of the year.
I would imagine the equipment uses standard railroad brake systems.
Then, again, I could be mistaken - it's possible that the "semi-permanent" connection is a hose, not a drawbar....
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...
I don't care if the train is brand new, things happen. A stuck valve, cracking wheel, broken safety device, grade crossing accident, bad brake pad, any number of issues that can and do happen to a car.
In most of the Mid West, especially where they originate these trains, how the hell you going to repair that? How are you going to get repair equipment to the car with snowdrifts up to your neck?? If the car cannot be repaired on-spot, what now with your permanent drawbars? No unit train will fit in a RIP track where lifts and equipment are.
And no railroad would purchase them, instead putting that upon the customers bill, so long as facilities are in place on the respective lines that can properly handle them.
Pipe Dream.
dehusmanBy the way, for those proposing a dedicated unit train that has drawbars and not couplers, how are you proposing it be loaded and unloaded? The operations I have seen break the train up into smaller cuts and load and unload those, and don't have a 100 car capacity loading or unloading rack. Does your design require that the loading and unloading facilities be also completely rebuilt to accommodate the train?
What Dave Klepper is proposing differs considerably from what I am proposing, so I won’t speak for him. What I am proposing requires a captive consist because it uses ECP brakes, and they will not be in universal use throughout the freight car fleet. I am proposing solid, semi-permanent drawbar connections. This would provide the maximum strength with the least weight, eliminate slack, and eliminate the electric cable connectors which have proved to be a somewhat problematic feature of ECP brakes. However having one separable coupler joint and one pair of electric connectors that would allow breaking the 100 car train in two would not be a problem.
Myf concept, based partly on Euclid's input, definitely does not use drawbars. There would be spare equipment. I would ask for the best possible mu-type couplers that incorporate the air and electrical connections, yet can when required mate with standard Janey MCB couplers. I would vote for individiual double-truck, tankcars, just the most robust design possible, with the brake, alternator-derailment responder, and battery equipmennt discussed.
dehusman By the way, for those proposing a dedicated unit train that has drawbars and not couplers, how are you proposing it be loaded and unloaded? The operations I have seen break the train up into smaller cuts and load and unload those, and don't have a 100 car capacity loading or unloading rack.
By the way, for those proposing a dedicated unit train that has drawbars and not couplers, how are you proposing it be loaded and unloaded? The operations I have seen break the train up into smaller cuts and load and unload those, and don't have a 100 car capacity loading or unloading rack.
This is a very valid point -- years ago, I'd have said it could be done via something like the Tank Train, but that approach doesn't work for a great many combinations of payload and unloading requirements.
Presumably the consist can be broken into sets with couplings that are more robust than a 'standard' interchange coupler, and that preserve the breaking and torsion strength of the drawbar/anticlimber setup. There is even some justification, if going to 'nonstandard' couplers that incorporate special ECP or track-brake connections, in making them 'especially strong' for this special service...
Is there a particular cut length that optimizes loading utility and service flexibility -- say, a ten-pack? This could rather easily be incorporated into the design...
Does your design require that the loading and unloading facilities be also completely rebuilt to accommodate the train?
Dave H. Painted side goes up. My website : wnbranch.com
The objections are valid, and we are talking only at this point of specialized equipment, an entire train kept together as a unit. Yes it can be coupled to other equipment, but then its special featurs would no longer be operable. We are talking about a complete train, with its own assigned locomotives. There already are such unit trains in operation, and some operate on more than one railroad.
It may be that after experience with this special equipment, ways will be found to adopt its special features to interchanged equipment, but that would be considerably in the future. Possibly for test purposes, one complete tank-car train would be constructed, number of cars dependent on the specific market and lane, number of diesel units based on the lane's railroads' own power for load figures, plus one for spare, plus a few spare tankcars as well. One goal is a train that is practicalliy derailment-free, break-in-two-free, as close to indestructable as possible, and that, even if 100 cars long, can stop approximately in the distance a private auto can stop at the same speed, without any stringing on curves, buckly, severe running in of slack, and a really easy train to handle.
There is nothing really that unusual about what I am proposing. It is just a new combination of practice that is already a part of real world railroading. The computer controlled brake derailment function is no big deal compared to a host of other ideas being seriously proposed by the FRA. It is also no big deal compared to all the technology planned for PTC.
ECP brakes are a radical breakthrough, and yet the basic concept has been around for a long time. But the march of technology has finally made the execution practical. The industry takes ECP brakes seriously because it offers important advantages over conventional air brakes. So, there is a desire to universally replace conventional air brakes with ECP brakes.
However, there is a problem that I believe will prevent that from happening. The problem is the sheer size of the universal application of the current system. Replacing that system must be a relatively quick and concerted effort because the benefits of ECP brakes do not really kick in until all or most cars are equipped. But a fast changeover is a financially staggering challenge. And during the changeover, the new system has to be compatible with the old system. This further drives up the cost of the new ECP system. And then once the changeover is complete, all of those extra compatibility features become instantly obsolete with a lot of life still remaining in them.
In reading the Booz Allen Hamilton report on ECP brakes, one can sense the irresistible enticement of ECP, but in reading about the challenge of conversion, one can sense that the universal conversion is a bridge too far. The industry realizes this, and so there have been proposals to add the system only to specialized unit trains where the cars stay together. That way, the advantages of ECP brakes can be realized in that select service without converting the entire U.S. and Canadian rolling stock and locomotive fleet.
Just in terms of marketing against this current oil train fireball problem, ECP brakes would be a good match with oil trains just for the public and regulatory perception of a major safety advancement for oil trains. They are often unit trains just as the industry was planning to equip with ECP brakes. This would not be so much an engineering breakthrough as it would be a natural application of what was basically the plan all along. But it would be a powerful tool for improving the image of oil trains at a time that it is desperately needed.
Then if you combine with the ECP, the special feature that I am proposing, along with some other features involving enhanced inseparability of couplers, you have a truly advanced system of safety that will mitigate the chance of rupturing tank cars in the case of many derailments. If it were not for ECP brakes, what I am proposing would not be possible. There is no way it could be done with conventional pneumatically controlled air brakes.
My oil train concept would benefit all freight trains, but again, because of the need to combine it with ECP brakes, and the challenge they pose to universal application, this derailment control concept would be best targeted just to oil trains because that is where it is needed most by far.
daveklepper I am assumiing unit trains of identacle cars loaded close to exactly the same way, well maintained, and with identacle brake eqhipment, regularly iinspected to insure that the brakes perform the same way on every car.
I am assumiing unit trains of identacle cars loaded close to exactly the same way, well maintained, and with identacle brake eqhipment, regularly iinspected to insure that the brakes perform the same way on every car.
That's a very shaky assumption. Unit trains are determined by the origin-destination and the billing, not by the equipment and there is no attempt whatsoever to match braking performance. The cars in an oil train are part of a pool and while its likely that certain groups of cars are moved together on successive trips there is no guarantee that they will remain on the train or route. It is relatively rare for all cars on a unit train to be exactly the same.
The only way they would remain together is if you make them equipment that is not compatible with other equipment so there is no choice but to run them together (an example are the Georgetown rock trains that can only be run in dedicated train sets.)
There is no test that measures the braking force of a car and there is no current requirement other than what is required on a normal brake test.
For the portion of the train forward of the accident (assuming there is break-in-two at the accident), the override button will provide the engineer to judge this situation and do what is necessary to minimze any damage first to people and then to property.
You will also have to assume that this train will be interchanged between two or more railroads over the course of a trip and may have more than one set of engines on it.
I see we are coming to agreement. I already posted that I am not recommending track brakes for loose car railroadiing, because of weight and rolling resistance differences between car and car. I am assumiing unit trains of identacle cars loaded close to exactly the same way, well maintained, and with identacle brake eqhipment, regularly iinspected to insure that the brakes perform the same way on every car. Small one or two percent differnces can be tolerated and pose any undue forces on couiplers. But I am assuming that the whole train acts as a unit, and under those circumstances, stoping the entire train behind the point of accident is certainly by far the safest procedure. For the portion of the train forward of the accident (assuming there is break-in-two at the accident), the override button will provide the engineer to judge this situation and do what is necessary to minimze any damage first to people and then to property. And the whole system uses off-the-shelf comoponents; all the technology exists now. Brakes: adapted from MU commuter rail and light rail technologies. Derailment detection: adapted from wheel-slip control.
Dave Klepper,
Just to clarify something, I am not assuming the normal current air-brake procedure, where the drop in pressure travels from the break-in-two to the rear at less than 1000 ft/sec. I have explained several times in this thread that I am proposing the use of ECP brakes, and that they are controlled by electrically powered valves on each car which are controlled by electronic signals sent through a wire. So I am talking about the same speed-of-light control that you are referring to in association with track brakes.
With a train experiencing a derailment, I agree that it would be beneficial to stop every car as quickly as possible. The quicker it all stops, the less opportunity for damage. However, if the quick stop force is not uniform throughout the train, it can cause more damage than if the stop were slower. In the case of track brakes, I understand your point that they provide greater stopping adhesion than brake shoes against wheels. The simultaneous application may indeed provide uniform stopping force throughout the train, and therefore, neither compress against the derailing cars from the rear, nor pull too hard on the derailing cars from the front.
But I am not sure that this effect is guaranteed to occur just because brakes are applied with the same force to all cars at the same time. The train may be running with part moving up grade and part moving down grade. This undulating profile would be likely to influence the rate of deceleration in different parts of the train despite uniform braking force throughout the train.
Incidentally, I need to restate my scenarios #1-3 in a preceding post. I said #3 is the desired outcome; however, it actually needs to be scenario #2; as long as the pull on the derailing cars is not so great that it pulls the train in two. This pull is needed to help keep the derailing cars in line as they are subjected to a lot of skewing forces while running on the ground.
Scenario #3 is valid, but it needs some clarification. If the braking deceleration in the cars ahead of, and behind the derailing cars were uniform, there would be no compression or tension on the derailing cars due to unequal braking deceleration.
Yet, as mentioned, there needs to be some tensile pull on the derailing cars; so on the face of it, scenario #3 seems like it would be insufficient. However, even though the braking deceleration ahead of and behind the derailment is equal, the derailing cars themselves will provide resistance, and that resistance will cause the cars ahead of the derailing cars to be pulling on the derailed cars.
So, scenarios #2 and #3 need to be re-written to make these points clear.
I am not saying your idea of stopping as quickly as possible won’t work. It is a different approach to the problem. Just ECP brakes alone might go a long way in preventing pileups just because of their simultaneous application. Aside from shorter stopping distance, I have no idea of the ramifications and tradeoffs of using track brakes on a freight train.
NO Again you don't know the facts. With magnetic track brakes on each car, there is no pile-up to speak of because each car brakes to a stop as fast as an automobile brakes to a stop in an emergency. You are assuming the normal current air-brake procedure, where the drop in pressure travels from the break-in-two to the rear at less than 1000 ft/sec. With the electrical control it passes from the front to the rear at the speed of light, the normal speed of an electrical impulse. And the magnetic track brakes will stop the cars as quickly as the derailed car will stop unless the derailed car has hit something solid or moving in the other direction, and the Frailey suggestions should minimize that. Your program will lead to your "1" in many cases, because you do not have any guide as to how quickly the derailed car will stop and cannot plan in advance the suitable compromize braking effort. Soil and roadbed conditions widely. My program wil usually lead to no, 2, which I consider an excellent result, that the cars on the track prevent the derailed car from going very far!
In fact, your example of the Milwaukee freight car that traveled four miles, would have been a very minor incident with my system. The train would have stopped completely, the whole train, the crew would get out the rerailing frog, pull the car with one truck derailed back onto the track, proceed very slowly, to the next siding, and set off the problem car for attention by the car department before anyone tried to move it further.
On further thought, only two axle generators are necessary, each one on the outer axle of the trucks, the outer axle to facilitate the very-seldom-requried mainentnance.
daveklepperI would prefer to leave the decision as to pulliing a way from a midtrain or rear derailed tank car as quickly as possible or stopping the whole train as quickly as possible in the hands of the engineer. I can imagine a scenereo where pulling away fast would cause more harm than good.
Either pulling away as fast as possible or stopping as fast as possible will do more harm than good.
The intention of the automatic derailment response that I am proposing is not to pull away from the derailment. That would perhaps reduce the number of cars involved by getting them clear of the pileup. However, pulling away requires that a drawbar breaks and the cars ahead of the derailment separate from the cars running on the ground.
Once that separation happens, the stage is set for the cars on the ground to pile up into a heap. So you don’t want to pull away. And you also don’t want to slow the head end down by excessive braking. You want to keep the cars ahead of the derailment moving freely, but not so freely that their inertia pulls the train in two somewhere ahead of, or within the derailment. The optimum condition would be for the car ahead to pull on the derailed cars enough to keep them roughly in line; and prevent the cars behind the derailed cars from pushing so hard that they buckle or jackknife the derailed cars.
Generally, there are three basic scenarios in a mid-train derailment:
1) The cars behind the derailment run in with hard compression against the cars ahead of it.
2) The cars behind the derailment resist the pull of the cars ahead of the derailment.
3) The cars ahead of and behind the derailment keep their rolling inertia matched so that the cars running on the ground are not compressed or pulled so hard that they separate.
What I am proposing is intended to yield result #3. That result is also possible with conventional air brakes, but rare. With conventional air brakes, scenarios #1 and #2 are the most likely.
Unlike what I am proposing, the full-train dynamiting brake response to a derailment and pileup is typical with conventional airbrakes due to the first parting of an air hose pair. That response does stop the train as quickly as possible, but it can worsen the effects of a derailment, particularly if it leads to scenario #1.
So what I am suggesting will stop the train quickly, but not as quickly as the automatic dynamiting response of conventional air brakes. I want to reduce the stopping deceleration somewhat in order to balance the forces through the derailment for the purpose of achieving scenario #3, and avoiding scenarios #1 and #2.
I would prefer to leave the decision as to pulliing a way from a midtrain or rear derailed tank car as quickly as possible or stopping the whole train as quickly as possible in the hands of the engineer. I can imagine a scenereo where pulling away fast would cause more harm than good.
Norm,
It will cost a lot of money. But it has to be designed and developed to find out how much it will cost. You have to start with a concept. It takes a lot of investment just to find the cost. And the cost can be brought down as manufacturing moves forward. Along with the costing, there has to be an accurate analysis of how much money this will save.
This system will save money in preventing broken trains, spilled oil, and damage litigation. That is the engineering objective. But I believe it will also save money by putting the brakes on regulation. That is the marketing objective.
In my opinion, making tank cars a little stronger over the next several years is not an adequate response to offset the problem that is coming at the industry. It seems like a mighty high stakes wager that oil trains will be lucky.
You should be discussing this with a computer/electronic engineer and programer to see if it's even possible and what equipment would be required, and the cost of the system. My guess is it's going to be much more complicated and cost prohibitive than you may think. Even if it can be done with computers the cost may kill the idea. The law of diminishing returns may find the cost far above and beyond the benefits.
Norm
tree68 EuclidThis information would be developed by a central processor that would know where the derailment is located, and so it would know where to split the braking function.And how, pray tell, will the processor know which car is where? If a car is bad-ordered and set out, how will the processor make the necessary adjustments? If the processor has to talk to each individual car, what will be the response time for the data to all the cars? Will there be some form of confirmation to the processor so it knows all cars have received the instructions? If you're talking wireless, what kind of range will the main processor and the individual cars have? If you're talking car-to-car relay via radio, what will be the failsafe if one car's processor fails?
EuclidThis information would be developed by a central processor that would know where the derailment is located, and so it would know where to split the braking function.
If the processor has to talk to each individual car, what will be the response time for the data to all the cars? Will there be some form of confirmation to the processor so it knows all cars have received the instructions?
If you're talking wireless, what kind of range will the main processor and the individual cars have? If you're talking car-to-car relay via radio, what will be the failsafe if one car's processor fails?
The processor would be independent of the cars and it would speak to all of them. I would expect the processor to talk to the cars and the cars would talk to the processor to confirm the receiving of commands from the processor. This much is part of the ECP brake systems currently under development.
Sensors to monitor brake performance are part of ECP, and additional sensors are contemplated because the communication cable of ECP is an essential component, and once incorporated, it can be used for other things like bearing temperature sensors. In the case of my proposal, there needs to be derailment sensors in addition to brake performance sensors. I would also consider other sensors. Considerable development would be needed for the derailment sensors. They might be a combination of sensors to monitor alignment, vibration, sound, etc.
The processor would have to know where all the cars are, and it would know that by the sensors sending information from each car. If a car were set out; the processor would detect that loss of that car and its position in the train, and then compensate for the lost car in its organization.
I don’t expect response time to be a problem, but I might need a little help wiring this thing up. A lot of thought and R&D would have to go into the automatic braking program. That is probably about the greatest area of development work needed.
Paul of Covington All this talk of sophisticated electronic devices is fun to think about, but having worked on electronic and electro-mechanical stuff, I can't help thinking about how robust this equipment is going to have to be. The railroad environment is very severe, with dirt, moisture, flying gravel, extremes of temperature, repeated jolts, etc. Going back to the idea of controlling the braking differently ahead of and behind the sensed derailment, how would the instructions be conveyed to the individual cars?
Going back to the idea of controlling the braking differently ahead of and behind the sensed derailment, how would the instructions be conveyed to the individual cars?
The severe conditions of the railroad environment do indeed require extra robustness in terms of the electronic hardware features for ECP brakes, particularly with plug connectors that would be routinely connected and disconnected on loose car ECP applications.
With ECP, the individual cars have their brakes controlled by an electronically controlled, electrically powered valve that takes the place of the pneumatically controlled, so-called “triple valve” of the conventional air brake system.
With the system I am proposing which separates the braking into two independent ranges, this information is conveyed to the ECP brakes via the normal electronic transmission cable from car to car. This information would be developed by a central processor that would know where the derailment is located, and so it would know where to split the braking function.
Paul, none of this is new technology. Electric control of braking is standard on all mu-cars and has been for over 100 years, ever since Frank Sprague electrified the Southside "L:in Chicago. It is actually more rugged, not less, than airpipe control of braking, but the catch for both is the connection between cars where both systems face the same problems. And wheel-slip detection on diesel and electric locmotives has been around for about 50 years, and the componants are rugged, proven, off-the-shelf, and all that would be required for derailment detection would be calibration to not act until differences are somewhat greater. I noted on earlier post that magnetic track brakes were in use on interurban cars of the West Penn from 1912, and some of these cars were still lin use at the end of service in 1953 with the same equipmenet intact and in good condition. Western PA has plenty of ice and snow and sleet. The result would be unit oil trains that would be safer than conventional manifest trains because they could stop as quckly as any truck, actually a lot quicker in ice or snow or rain. Possibly as quickly as a private automobile on dry pavement.
I have never worked for a railroad, but I thought I might throw in a couple of comments.
All this talk of sophisticated electronic devices is fun to think about, but having worked on electronic and electro-mechanical stuff, I can't help thinking about how robust this equipment is going to have to be. The railroad environment is very severe, with dirt, moisture, flying gravel, extremes of temperature, repeated jolts, etc.
In my experience false error detection seemed to be about as common as real errors. Considering the rough environment this may be more of a nuisance than help.
_____________
"A stranger's just a friend you ain't met yet." --- Dave Gardner
The current cars leak even without derailing (12,000 gallons along the CP south of Red Wing, MN):
http://www.winonadailynews.com/news/local/gallons-of-crude-oil-spilled-between-winona-and-red-wing/article_850d10d2-a702-5fc8-b97e-f822d0c5c30b.html
C&NW, CA&E, MILW, CGW and IC fan
The correct derailment sensing device is simply a varation on diesel (and electric) locomotive slip control. Instead of just one axle generator for emergency use of the magnetic track brakes if the battery is exhuusted by deceleration from speed on a downgrade, and any modern generator would be an alternator with rectification to avoid brush and commutator maintenance, have one for each axle and a frequency comparitor that would signal for an emergency application if there is great discrepency between rotating speed of one axle as compared with any of the other four. This might protect from some other problems besides derailments.
Remember that with magnetic track brakes and electric application of brakes, indeed the whole train stops as a unit, with NO accordianing or breaking in two or pulling off on the concave side of a curve.
I am assuming decently maintained equipment, all of the same characteristics throughout the train. This whole system is for unit oil trains and other unit hasmat trains, not for loose car railroading by any means. Alhtough electric control of braking would benefit loose car railroading, to try to calibrate the magnetic track brake forces for different cars with different weights would be very complicated and failure to do it properly could result in train handling problems, in an emergency, that would really complicate its usefulness.
Dave Husman,
Regarding my description of a case in which a car was dragged on the ties for 4 ½ miles, let me clarify my point:
I did not intend this to be an example of something that my proposal would have prevented or even reacted to. I agree that it is on the fringe of derailment occurrences. And as you say, it did not develop into a pileup involving additional cars, so my derailment control concept would not have been needed in this case. However, it does illustrate the kind of effect that my system is intended to produce with one or more derailed cars.
But the main point of this long dragging event example is to show that a car does not instantly plow into the ties and stop on a dime just because it derails.
dehusmanAttach two pneumatic cylinders between the truck bolster and the frame/body of the car. One on each side. The cylinders would have the chambers on each side of the piston connected so as the truck turns, they vent from one chamber into the other so there is minimal resistance to turning in normal operation. The arrangement should be constructed so when the piston is centered the trucks are running straight. Use Euclid's derailment detector to detect when the car derails. When the car derails, pressurized air/gas is vented into the cylinders, centering the pistons and steering the truck to run straight. If you wanted really fast action, you could use the same technology as air bags to almost instantly create high pressures in the cylinders. That would give you reaction times in the hundredths of seconds rather than seconds. The truck would be steered into a straight ahead line and the pressure in the cylinders would keep it straight. Since the truck isn't on the rail, concern about the rigid truck failing to negotiate a curve isn't a problem.
Oh, great; let's put mandatory pyrotechnic charges on oil cars, and fire them whenever a computer detects what it thinks is a derailment. Then let's center a three-piece truck by whacking on the bolster, with the wheelsets presumably derailed and leverage acting to skew the sideframes against the bolster. And while we're at it, center it relative to the center sill of the car even if the train is traversing a curve.
I could go on, but that's really enough to can the idea. Quickly, to minimize the shuddering... ;-}
(I considered using servos years ago, to deal with issues of harmonically-driven truck skew/lozenging. The cylinders would be driven so as to move the bolster counter to the skew moments and re-establish seating of the sideframes on the bolster, and the bearings in the sideframes. Dropped the idea relatively quickly, because driving such a system out of perfect calculated phase might actually amplify the problem rather than solve it -- and there were other problems with the idea, too, that I won't go into.)
The basic idea of keeping truck frames relatively parallel to car underframes is probably just as well served with crossed progressive return springs and some sort of rotation lock, either actuated inertially or via the brake system if you want to allow a further degree of truck rotation on crossovers or whatever than the centering system would optimally allow. But I'm still unsure as to how much this arrangement alone will keep derailed cars tracking 'away from parallel trains on adjacent tracks' -- or how it's somehow better than maintaining longitudinal tension across the derailed car, as Euclid's system purports to do.
OH YES, of course I do not object in anyway to ading Euclid's derailment sensing device. With track brakes applying on each car, there should be no accordian effect. Or only one or two cars behind the derailment, not the whole rest of the train.
I differ. I think stopping the whole train, front to back, as quickly as possible without any additional damage, is by far the safest tactic, and the way to do it is with magnetic track brakes and all brakes controlled electrically. Each tank car of a unt train would have one axle-driven generator, and a battery . The battery would normally be charged by head-end power, and both electrical control and power to charge batteries would be bult into the couplers, similar to those mu-car couplers that are also compatible with MCB-Janney standard couplers. As with light rail, the magnetic track brakes would be an emergency use feature. A derailment usually (not always) invovles a break-in-two. Airbrakes would apply as in any break-in-to, but so would the magnetic track brakes. Until battery power is depleted, the track-brakes would be powered from the battery, and in most cases the specific car would come to a halt before the battery is deplected. But after it is depleted, if wheels are still turning, the axle-generator would suppliy power to the track brakes. This tactic would come into play on emergencies on a donwgrade when the event occurs at normal track speed. Without this feature, enormous batteries would be required. Electrical equipment and batteries would be clad to insure zero possibility of any electrical fire.
I cannot see any situaltion where this would not be of benefit except: If the event occurs mid-train or at the rear, and the main object is for the crew in the engine to get away as fast possible and get tanks at the front away as fast as possible, then the engineer immediateliy presses an override control, the rear of the train continiiues to stop as fast as possible and the front of the train accelerates away from the event as fast as possible.
I hope BNSF or Fortress or someone will build such a safe unit tankcar train and run the tests on it.
Euclid I doubt that it was covered in the news, but I was there the day it happened, about 4 hours after it happened. The dragging car was in the middle of a long train, and crew on either end did not see it. It happend very early in the morning and may not have been light yet. It was an eastbound train that dragged the car from just west of Chanhassen, MN to near Tower E-14. It tore out two planked grade crossings along the way, one at Duck Lake Rd. and the other at Birch Island Road.
I doubt that it was covered in the news, but I was there the day it happened, about 4 hours after it happened. The dragging car was in the middle of a long train, and crew on either end did not see it. It happend very early in the morning and may not have been light yet. It was an eastbound train that dragged the car from just west of Chanhassen, MN to near Tower E-14. It tore out two planked grade crossings along the way, one at Duck Lake Rd. and the other at Birch Island Road.
I suppose this was meant to justify the system Euclid is proposing. I see it as actually pretty much the opposite.
This situation presents the optimal situation for Euclid's system to work. The derailed car remains upright, trucks in line, on the ties, and no further cars derail.
The thing I would suggest be considered is the outcome. The cars didn't accordion. The cars didn't pile up. The train was brought to a stop. In short, the derailment was "survivable". Without ECP, without a sophisticated air control system, without alignment control drawbars. In short, without Euclid's system. Euclid is designing a system to control a situation where the control isn't needed. If you have the conditions to make Euclid's system work perfectly, then you have a situation where you really don't need Euclid's system to have a survivable outcome.
The question that has to be asked is why didn't the cars pile up? What was the condition that allowed the "survivable" outcome?
We don't know whether the train was stretched or bunched from the information we have.
What we do know it that the trucks stayed in line on the ties. Maybe rather than controlling the braking we should figure out how keep the trucks from going off the ties? If we keep the wheels on the ties we are more likely to end up with a survivable derailment.
Attach two pneumatic cylinders between the truck bolster and the frame/body of the car. One on each side. The cylinders would have the chambers on each side of the piston connected so as the truck turns, they vent from one chamber into the other so there is minimal resistance to turning in normal operation. The arrangement should be constructed so when the piston is centered the trucks are running straight. Use Euclid's derailment detector to detect when the car derails. When the car derails, pressurized air/gas is vented into the cylinders, centering the pistons and steering the truck to run straight. If you wanted really fast action, you could use the same technology as air bags to almost instantly create high pressures in the cylinders. That would give you reaction times in the hundredths of seconds rather than seconds. The truck would be steered into a straight ahead line and the pressure in the cylinders would keep it straight. Since the truck isn't on the rail, concern about the rigid truck failing to negotiate a curve isn't a problem.
If you want the derailment detector can initiate a penalty reduction to bring the train to a stop.
This solution can be retrofitted to existing cars. It doesn't require dedicated train sets. It doesn't require changing the car's couplers. It doesn't require a new brake system. It can work just as well in a train of conventional cars. It doesn't require complicated communication protocols. It could be made to have a very fast reaction time. It creates a more "survivable" situation. Its a much lower cost system. It addresses the root cause of a pileup.
Pretty much any situation that would overwhelm this solution would overwhelm Euclid's solution also.
Overmod,
Thanks for your objective comments and for understanding what I am proposing. Now that you have clarified your earlier comment, I understand your concerns about inadvertent dynamiting not being limited to the conventional pneumatically controlled air brake system. That would have to be worked out to prevent unintended consequences. I am not sure about the fine points of individual car brake control with ECP brakes. It may be conceptually possible, but not ever happen in practice. The big benefit of ECP is that the brakes apply simultaneously rather than sequentially over a period of time as is the case with standard air brakes. I would be very interested in learning about any research that goes beyond that and looks at applying the ECP brakes in an intended sequence for some reason.
With what I am proposing, the braking is divided into two independent zones (ahead of and behind the derailment), but for the most part, the braking force would be retarded on the leading zone cars to keep them from resisting the trailing zone cars pushing into the derailed cars. But a lot of control software would have to be developed, and some individualizing of the control beyond just the two zones might be desirable.
I think the automatic derailment response system I am proposing should be capable of being overridden manually by the engineer in case it falsely senses a derailment and initiates without a reason. The issue would not be that the system causes a violent stop that is unnecessary. The derailment control brake application would actually cause a relatively slow stop in most cases.
But if the automatic system had initiated and could not be overridden, it would prevent an emergency or harder stop from being made by the engineer if an actual emergency suddenly arose. In that regard, there might be times when the system is properly responding to an actual derailment, and it becomes necessary to override it, and stop faster for another emergency regardless of the loss of control of the derailment in process.
EuclidThe ECP brakes in this system will be controlled by wire, but will need some type of wireless backup for this derailment mitigation feature. There won’t be multiple dynamiters, as you suggest, because the system will not dynamite the brakes in the traditional sense of a rapid loss of train line pressure triggering a pneumatic chain reaction of emergency braking.
There has been a great deal of frankly amusing criticism of Euclid's ECP-braked idea, with very little seeming knowledge of what he was actually saying. Think of his system as having an individual brake controller on each car, which can be commanded either to apply or to release 'as appropriate' without any requirement for control latency. This could easily be done with a wired 'bus' system like the CAN bus in vehicles (controller area network) but it's probably less expensive to do it with a modern parallel wireless protocol (say a modulation scheme similar to OFDM). Then assume there is a computer system that calculates how every valve should be positioned, at least several times a second. The 'innovation' in Euclid's system is that if his system detects a derailed car, it automagically modulates the brakes on a few of the cars to the rear of the derailment in such a way that they don't 'bunch' to the point slack effects start to happen, but slow down enough to maintain tension across the derailed car and keep it from being pushed out of line and start the accordion playing. (Meanwhile, the head end brakes are applied just enough to keep the derailed car from pushing against the car in front of it, so In all probability the overall time it will take for the train to stop will be somewhat longer than a 'normal' commanded stop would be...)
The 'catch' is that in order for the system to have sufficient response characteristics to work, it must be capable of modulating the brake valves very quickly, and with sufficient power to get the brakes to apply net of all slack in the brake rigging within a comparatively short time. And that means that if the computer system 'glitches', or is improperly coded and generates any one of a number of false signals, there can be very great problems developing in a very short time.
When I said 'dynamiters' I was not referring to overly sensitive conventional triples -- I was referring to what would happen if the computer system overmodulated the brake valves in the following cut of cars -- perhaps it was coded by the bright folks responsible for trains of zero length in NAJPTC and mistakenly assumes the cars each weigh 32,768 tons apiece, or its GPS goes to a different epoch and suddenly thinks it is descending a grade somewhere in Outer Mongolia -- so that the controller goes to full excursion as fast as its little dashpot lets it go (and as I noted, that has to be pretty fast for the system to work right as intended, as the latency between the actual derailment and the time the system has detected it, calculated a response, and had the commands confirmed is likely to occupy a critical length of time). Or an engineer forgot to Gray code the signal coming off the encoder on a rotair valve, so one bad bit in a transmitted control signal produces a disproportionate degree of commanded rotation. Anyone remember when an early BART car given an 8mph control signal read it as '88', went to full acceleration, and over the end of available track?
I might be somewhat less nervous if I knew the system was built and mainteined by skilled and motivated graduate engineers. (Not to be disparaging of carmen, be it noted -- just that carmen aren't likely to recognize a great many of the complex interactions that might cause either dramatic overapplication or underapplication of the necessarily complicated response to an unpredictable derailment event. Or understand when a computer system thinks it detects a derailment when one hasn't occurred... or misses one that has.)
Note that the 'optimum' brake response to a derailment situation is NOT necessarily going to be an emergency stop -- on the other hand, if the derailed truck 'digs into the ties' it might be a very short stop indeed, right up to what's commanded.
Which brings me to the electromagnetic track brake.
There have been versions of this, with VERY quick stopping time, around since at least the 1880s. One nifty version by Frank Sprague (of later MU control fame) involved a long 'shoe' parallel to the railhead, aligned by springs and levers, on a linkage of struts that would let it hinge down so the weight of the car would press the shoe material hard against the railhead. This would be held up by an electromagnet, or a trip that would be released if the air pressure fell very quickly through 26 psi of reduction or whatever, or by some sort of inertia-switch arrangement: it is not difficult to see that if this thing gets released, that car is going to STOP. And a train composed of such cars isn't going to take much longer, even if there is considerable inertia involved. The 'wrong' sort of bottom-feeding plaintiff's-bar attorneys have probably read all the old issues of Scientific American, and have figured out that the only real difference between stopping 1880s cars and modern ones is a difference of mass... so when evil railroad representatives talk about freight trains needing over a mile to stop, it's just one of those minimize-the-cost-of-a-human-life things...
... until you watch what happens when the brake releases unespectedly on just one car. Or deploys on a curve, or on a train wrapped around a reverse curve, or deploys 'normally' and leaves a crew with 130 wedged-down shoes at one-dark-thirty and thunder and rain. When a safety system causes more, or worse, accidents than the conditions it was intended to remediate, I not-so-humbly suggest that there may be a reason it wasn't more fully adopted.
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