I have a suggestion to Euclid. Go build and test it then come back and tell us your sucess and failure. You will have some sucess but you will also have some failure. That is the way life is. Your not paying us on this blog-- remember you get what you pay for.
Euclid, you want to stop the accordion Pile ups on a derailment, no?
1. you will NEED more than brakes , bars and a ECP
2. Do ANY of you know how a tiny "Smart" Car got passed the crash tests? It simply transferred the energy by ROLLING away from the impact scene.
3. Knowing which car has derailed in an instant. Magnets on inside of wheels, with sensors on the trucks. In other applications these are flush mounted. Sensor pointed at inside of rail can tell if car truck isnt located correctly side to side. These would be checked thousands of times per second, like they are now in a typical ABS brake system in a car..INSTANT detection of wayward truck is possible.
4. After detection.. slowing the train, while keeping tension, or upright, is ONLY possible IF there is enough Braking available BEHIND the derail, and enough extra energy Absorbed in FRONT of the derail. Even still, the amount of energy, MOMENTUM, would overcome ANY Braking system ( the mechanical parts of any system) Slowing only 1/50th of the mass will not stop an accordion pile up
5. Euclid >QUOTE" But the way I address it is not to dissipate the energy faster than it normally dissipates. The way I address it is to control the energy so it does not get dissipated by crushing tank cars. " <, End Quote.
That is TOO much energy to "Control" without transfer of about 50 times MORE energy than all the brakes turned on in an instant... The ONLY way to implement a system like yours and have it work, is to have some HELP with the Momentum to dissipate ALL the excess energy. Current trains are NOT "mechanically" equipped to handle their mass in a crisis situation.
In Theory Euclid, your system , minus the extra draw bars, or chains, "could" Help the situation at a derail, but its NOT going to work on its own. There is Just way to much Energy, and its in Motion... " A body in motion, tends to STAY in Motion"
BARFlyer Euclid, Go ahead and take credit for your version of the ECP. Smart train cars make sense. You have repeated your "IDEA" many many times. Rarely, if at all, in the real world, do Ideas, as thought up, get implemented. Beating it to death here will not work. Your system lacks in dynamics other than straight ahead. ..Pile ups, which you are trying to avoid, can only be avoided when some excess energy is absorbed. Tougher cars, Draw bars,lower CG, isn't addressing the ENERGY at hand. ECM's currently in use can do the "ECP" job with sensors on the cars. Bigger braking surfaces can help, but brakes are only going to capture about 1/50th of the moving force in a 30 unit train. ECP or not the Loaded energy is too great without suitable absorption. Compressible, energy absorbing, superbly equipped braking Dynamometer cars, with heat exchangers on board is the only viable solution for the energy. These could work with a system of YOUR mention. Having done some experiments with this, on scale, I can assure you the brakes and the friction surface they encompass on the track, are NOT good enough. Fast response can help , but not enough. Possibly, the Energy absorbing car could "carry" extra trucks which could be deployed in an instant to help braking.. This problem will take a BUNCH heads, Half fixing it, its going to fly in the RR world, not with the press looking for blood these days.
Euclid, Go ahead and take credit for your version of the ECP. Smart train cars make sense. You have repeated your "IDEA" many many times. Rarely, if at all, in the real world, do Ideas, as thought up, get implemented. Beating it to death here will not work. Your system lacks in dynamics other than straight ahead. ..Pile ups, which you are trying to avoid, can only be avoided when some excess energy is absorbed. Tougher cars, Draw bars,lower CG, isn't addressing the ENERGY at hand. ECM's currently in use can do the "ECP" job with sensors on the cars. Bigger braking surfaces can help, but brakes are only going to capture about 1/50th of the moving force in a 30 unit train. ECP or not the Loaded energy is too great without suitable absorption. Compressible, energy absorbing, superbly equipped braking Dynamometer cars, with heat exchangers on board is the only viable solution for the energy. These could work with a system of YOUR mention. Having done some experiments with this, on scale, I can assure you the brakes and the friction surface they encompass on the track, are NOT good enough. Fast response can help , but not enough. Possibly, the Energy absorbing car could "carry" extra trucks which could be deployed in an instant to help braking.. This problem will take a BUNCH heads, Half fixing it, its going to fly in the RR world, not with the press looking for blood these days.
BARFlyer,
You might be confusing my proposal with Dave Klepper’s proposal since that has been discussed extensively in this thread. I am not trying to dissipate the kinetic energy of the train as quickly as possible, as Dave intends. So, contrary to your interpretation of what I am proposing, it is indeed my precise intent to address “the ENERGY as hand,” as you say.
But the way I address it is not to dissipate the energy faster than it normally dissipates. The way I address it is to control the energy so it does not get dissipated by crushing tank cars.
Overmod His differential brakes are no more hard on bridges (or other civil) than any alternative, particularly ballasted-deck bridges.
His differential brakes are no more hard on bridges (or other civil) than any alternative, particularly ballasted-deck bridges.
Since his plan calls for braking less than emergency, it will be less than a conventional train (which of course means stopping distances will be longer)
I think the concern is with the additional weight of the 'safe' unit train, ...
There is no additional weight, the cars are limited to either 263,000 or 286,000 lbs. so if you increase the weight of the car you limit the capacity (more car = less oil) . But in any case the weight of the car has an upper bound.
Dave H. Painted side goes up. My website : wnbranch.com
matthew.brandleyIn cx territory it would first have to start with the massive replacement of almost every bridge that wa built around the beginning of the 1900 s before you could even beging to even think of doing something like that. Almost evry bridge in the phila baltimore area that I know of wa built around that time and has yet to be replaced
His differential brakes are no more hard on bridges (or other civil) than any alternative, particularly ballasted-deck bridges. The actual braking effort to achieve the differential action is less, not more, than a conventional emergency-brake actuation, although it is possible that very short periods of actuation would be stronger at a given time during an ECP braking event than their conventional counterparts at the same time in the braking run.
I think the concern is with the additional weight of the 'safe' unit train, and it might be sensible at this point to provide a precise Cooper loading for a loaded oil train using this system -- I'd be surprised to find it that much higher than, say, a conventional HAL stack train as to justify massive ROW and infrastructure improvements.
Not that I'm against checking and rebuilding 100-year-old assets on a regular basis!
In cx territory it would first have to start with the massive replacement of almost every bridge that wa built around the beginning of the 1900 s before you could even beging to even think of doing something like that. Almost evry bridge in the phila baltimore area that I know of wa built around that time and has yet to be replaced
Euclid In the most fundamental sense, my concept proposal requires that the ECP brakes can communicate with, and control the brakes on each car independently, so braking power can be varied from car to car within the train. As far as I know, this is not a normal requirement with ECP brakes, so they are not equipped with this functional ability. They apply braking to every car in the train as a whole, and if braking force is to be varied, all cars remain synchronized to that variation. So the ECP system does not need to identify individual cars within the train. It treats them all the same.
In the most fundamental sense, my concept proposal requires that the ECP brakes can communicate with, and control the brakes on each car independently, so braking power can be varied from car to car within the train. As far as I know, this is not a normal requirement with ECP brakes, so they are not equipped with this functional ability. They apply braking to every car in the train as a whole, and if braking force is to be varied, all cars remain synchronized to that variation. So the ECP system does not need to identify individual cars within the train. It treats them all the same.
"Basic" ECP will have a control input from load cells in the trucks or bolsters, controlling the brake application relative to the car weight. This gets around having to use any kind of decelakron/decelostat system to modulate deceleration, pick up speed from an axle, etc. as would be done for passenger cars.
As a result, the braking integrity does not depend on where in the train a given car is located. And it may not be necessary to integrate the car-order report for a given train with the brake control algorithm (as would currently get the job done in contemporary railroading without a complex protocol for determining the physical locations of the cars...).
However, the ECP braking that I am proposing for derailment control must be able to identify individual cars in the train in order to create the necessary differing patterns of brake application.
And this is precisely what requires positional determination. One way to accomplish this in a pure distributed system is to have an ID on the car, and have any adjacent car capable of reading this ID and understanding that the ID is its 'neighbor' at one end.
Then when the computer polls the consist, it gets 'ordered triplets' of IDs and can compile a train order from these data without any need for sequential reading or trying to get positions via, say, embedded NDGPS (which can actually do the trick most of the time, and is a useful 'check' when it's working, but shouldn't be relied on as an absolute reference...)
The way to accomplish this is to simply assign each car an identification number that can be read by the ECP brain in the controller on board the locomotive. Then the brain can detect the locational order of these identification numbers from one end of the communication cable to the other. Therefore, you could assemble any of the cars in any random sequence, and the ECP controller would know where they are in the train. You would have to do an explicit 'scan' of the bus, but how does the 'brain' know which address is located where? The physical cable is only the minimum number of conductors to implement something like CANbus, and probably nothing more intricate that twisted-pair for each direction of backbone. Time-of-flight might work, but you would need something like a built-in TDR across multiple, uncertain-quality physical connections, and that's not likely to be workable in the long term, even if it could be made to work under lab conditions. As noted, you could do data fusion with the manifest or consist, which would give you the positions of the car numbers (and thence allow reference to the IDs) in the train. But if there is a mistake, GIGO (and that is NOT a desirable mode for a safety-critical system!) As I recommended, if you have multiple vibration monitors on the trucks, use those as the reference IDs, with some method of determining which wheel on the car gets which ID (it will change with the truck frames, as the monitors are incorporated on them), and then have each car interrogate its neighbor 'periodically' and keep comparing the result in order to derive the positional aggregate. (You can always arrange to check it against the manifest order, if you're nine-nines paranoid about critical data integrity...) That way, when a derailment occurs with say car number 44678895, the controller will know the identification and order of all the cars ahead of the derailed car and of the cars behind it. Therefore, the controller will be able to vary the braking force applied to those two separate ranges of cars for the purpose of stabilizing the derailment action the instant it begins. Which is precisely the differential braking that we've been talking about all this time. One thing that I think could be gainfully added is a small strain-gage-like sensor that reads buff and draft for each end of the car. (You need to know 'car end' to resolve the eight vibration modules correctly in train, so nothing is necessarily added by having an A and a B end, and the controller doesn't care whether the A or B end is leading on any particular day...) This gives a direct reading on the tension between cars, either as a backstop for the positional information or as a control input for the proportional braking. (It will also help with a variety of other operational issues, for example management of the node in DPU operations...) There is nothing new in modulating ECP proportionally on a car-by-car basis; the novelty is entirely in using the braking to keep sensitive and proportional tension across a putatively derailed car... or, for that matter, across what may be multiple 'islands' of derailed cars as the train decelerates, or to manage the situation if there is a break-in-two so the rear end doesn't collide with the front (now you see a critical reason I want to make the network like a wireless PAN instead of relying on cable continuity in the consist?)
The way to accomplish this is to simply assign each car an identification number that can be read by the ECP brain in the controller on board the locomotive. Then the brain can detect the locational order of these identification numbers from one end of the communication cable to the other. Therefore, you could assemble any of the cars in any random sequence, and the ECP controller would know where they are in the train.
You would have to do an explicit 'scan' of the bus, but how does the 'brain' know which address is located where? The physical cable is only the minimum number of conductors to implement something like CANbus, and probably nothing more intricate that twisted-pair for each direction of backbone. Time-of-flight might work, but you would need something like a built-in TDR across multiple, uncertain-quality physical connections, and that's not likely to be workable in the long term, even if it could be made to work under lab conditions.
As noted, you could do data fusion with the manifest or consist, which would give you the positions of the car numbers (and thence allow reference to the IDs) in the train. But if there is a mistake, GIGO (and that is NOT a desirable mode for a safety-critical system!)
As I recommended, if you have multiple vibration monitors on the trucks, use those as the reference IDs, with some method of determining which wheel on the car gets which ID (it will change with the truck frames, as the monitors are incorporated on them), and then have each car interrogate its neighbor 'periodically' and keep comparing the result in order to derive the positional aggregate. (You can always arrange to check it against the manifest order, if you're nine-nines paranoid about critical data integrity...)
That way, when a derailment occurs with say car number 44678895, the controller will know the identification and order of all the cars ahead of the derailed car and of the cars behind it. Therefore, the controller will be able to vary the braking force applied to those two separate ranges of cars for the purpose of stabilizing the derailment action the instant it begins.
Which is precisely the differential braking that we've been talking about all this time.
One thing that I think could be gainfully added is a small strain-gage-like sensor that reads buff and draft for each end of the car. (You need to know 'car end' to resolve the eight vibration modules correctly in train, so nothing is necessarily added by having an A and a B end, and the controller doesn't care whether the A or B end is leading on any particular day...) This gives a direct reading on the tension between cars, either as a backstop for the positional information or as a control input for the proportional braking. (It will also help with a variety of other operational issues, for example management of the node in DPU operations...)
There is nothing new in modulating ECP proportionally on a car-by-car basis; the novelty is entirely in using the braking to keep sensitive and proportional tension across a putatively derailed car... or, for that matter, across what may be multiple 'islands' of derailed cars as the train decelerates, or to manage the situation if there is a break-in-two so the rear end doesn't collide with the front (now you see a critical reason I want to make the network like a wireless PAN instead of relying on cable continuity in the consist?)
This safer oil train concept that I am proposing uses electronically controlled pneumatic (ECP) brakes which are currently used in specialized railroad applications. For the most part, ECP brakes are fully developed, and are preferred over conventional automatic air brakes, but the universal conversion is still a long way off due to the need for 100% commitment to that conversion and the cost of doing that.
However, what I am proposing is using ECP brakes only on specialized oil trains operating as unit trains composed of captive rolling stock. Then I am adding a new feature to the standard ECP brake system for the purpose of mitigating the crushing damage caused during a derailment.
As far as I know, nobody else has proposed extending the ECP brake concept into the sort of derailment control function that I am proposing here, but the extension falls naturally into the basic operation and attributes of ECP brake systems.
However, the ECP braking that I am proposing for derailment control must be able to identify individual cars in the train in order to create the necessary differing patterns of brake application. The way to accomplish this is to simply assign each car an identification number that can be read by the ECP brain in the controller on board the locomotive. Then the brain can detect the locational order of these identification numbers from one end of the communication cable to the other.
Therefore, you could assemble any of the cars in any random sequence, and the ECP controller would know where they are in the train. That way, when a derailment occurs with say car number 44678895, the controller will know the identification and order of all the cars ahead of the derailed car and of the cars behind it. Therefore, the controller will be able to vary the braking force applied to those two separate ranges of cars for the purpose of stabilizing the derailment action the instant it begins.
BNSF has taken the leap and with Greenbrier is designing a new tank car. With all the bells and whistles that has been suggested in this blog there has been little to no discussion about one important item-- the center of gravity. As far as slosh in a retangular container in concerned---that's what baffels are far. It will be interesting to see what Greenbrier dreams up and how it test at Pubelo.
I'm surprised there hasn't been any comment on the agreement reached between the AAR and DOT on the operation of CBR trains.
Lets look at some known facts.
1. Computers in Automobiles can sense and execute commands at Thousands per second. An example is the solenoids in the valve body of your automatic transmissions. This means having each Train car a "smart" car is inevitable.
2. Sensors on wheels/rotors, gears, is easy and cheap. In this case we do NOT want to STOP the wheels during any braking, we want to slow them down. A slipping wheel slows down a train car LESS than a wheel with some traction.
3. This should be heading in an ABS direction then, keep the wheels behind a derail in anti lock but heavy brake mode.
4. Switching brakes ( Engineer /the Engine) takes a lot of time
5. Magnetic Brakes.. The required Power to run them effectively in the heavyweight class would be just way expensive and would be needed per car. I also seem to recall problems with "Rust" on these units. A great idea though, and was used in the highway industry and still is in some areas.
6 ENERGY. Its been mentioned a bunch in this thread, but No real solutions to all the energy that's pushing a moving train. Its really hard to figure all the outcomes as its not as simple as Force in ONE direction. Many derails happen on curves, and the forces will just want to move on Straight ahead. No Draw bar or chain will stop that. Brakes, EPC, antilock, ABS, None will stop or even slow a 45 mph oil train down enough to prevent a Pile up.
To make this EPC, brake sensing, or even ABS system work, while computer controlled, it will need Help Absorbing lots of force. The ONLY way this can happen is with a "EAC" Energy Absorption Car", or a few per consist. These would have to be as long as an Oil car and have the capability to absorb shock and pressure, with air, hydraulic shocks/ etc.They may have a different truck system with more braking abilities than a normal tank car as well. Also, equipped as a "smart car" it would be able to measure and report the forces for future use in construction, like a Dynamometer car has been doing for over many decades. This is NOT a "buffer" car as they are used/called today.
ALL of the above technology is being done today in many forms, its not new.
Euclid, I approve completely of each car being a smart car with evaluation of the exact situation, with respect to what it is doing, where it is, and what the adjacent cars are doing. Then, if proportional braking is the safest measure at the time, that is what will happen. If the fastest braking is the safest measure at the, that is what will happen. I am unsure how long such a development will take, and I think my approach is a good interem step.
Overmod,
My intention is to retain the conventional brake rigging foundation, brake beams, and wheel tread brakes as currently used on tank cars. I would only revise the components as necessary to convert from conventional pneumatically controlled air brakes to electronically controlled air brakes or “ECP brakes.”
The operation would simply apply and release air pressure to the air brake cylinder. I am thinking about the basis for your points about the computer needing to know the position of the shoe relative to the tread, and the computer needing to track slack adjustment.
I believe this brake shoe slack would close up quite fast even with a small amount of air pressure if that pressure could be built up quickly in the airbrake cylinder. So, if the intent were to build only a small pressure preliminarily, that would best be accomplished by a very quick shot of air at a high flow, which would abruptly cut off. This shot may only last for a tenth of a second, for example.
That action would take the slack out of the brake linkage and set the shoes against the wheels. Then those brakes would be staged for instant braking effect once the airbrake cylinder pressure is increased. So I guess that staged position would be the “baseline” that you refer to.
This effect of staging the brakes with only a very small brake cylinder pressure would typically be executed only on the cars ahead of the derailment, and only to the extent that there are relatively fewer cars ahead of the derailment than behind. If for instance, there were 20 cars ahead of the derailment and 80 cars behind it, the 20 cars would be staged with brake shoe slack removed. The brakes on the 80 cars behind the derailment would immediately begin a heavy application in order to stop the train.
But this heavy application would not go to full pressure instantly. It would apply to all cars behind the derailment at the same time, but the pressure would build in a progressive “ramp-up” in order to prevent a sudden tensile shock into the derailing cars and the cars still on the rails ahead of the derailing cars. This progressive ramp-up would prevent that tensile shock from breaking the train in two, either in the derailed cars, or the cars ahead of the derailment. The ramp-up might last for say ten seconds, for example.
If there were 80 cars ahead of the derailment and 20 cars behind it, there would be no preliminary staging of the brake shoes to remove their slack. The brakes on both sections would immediately go to heavy application, but with less application to the brakes on the 80 cars ahead of the derailment than on the 20 cars behind it. Some ramp-up for the application to each section of cars might be advisable, but this needs to be analyzed for the design of the program, and I would expect it to vary according to the ratio of cars ahead of and behind the derailment. It would also vary according to other conditions such as train speed and location on the line.
midwest member Sounds like you have described a "well car" with disc brakes.
Sounds like you have described a "well car" with disc brakes.
Disc brakes are relatively difficult to implement on a three-piece truck. What he's basically talking about with ECP is electronic proportional control of the actual braking effort, moment to moment, rather than the existing system where actuation is (analog) proportional, but release is not.
Theoretically it is not much more difficult to implement proportional tread braking, even on three-piece trucks that use floating brake beams and long rods and levers. If you keep the existing foundation, it greatly reduces the potential cost of the swap to a safer brake system (and the interworkability of an ECP car with those equipped only with 'legacy' air brake).
Even in unit trains of the type Euclid is suggesting, retaining much of the current type of brake gear is likely to be a sensible approach costwise, particularly where maintenance and adjustment is concerned.
There are two added 'inputs' to the differential-braking system: the computer must know the position of the shoe relative to the tread, and the slack adjustment has to be tracked. I suspect there will be some device that quickly takes up all slack in the gear while applying no more than a few pounds of actual retarding force when the 'derailment' system is first actuated; all the follow-on brake modulation would use that position as a baseline.
dehusman Euclid When I refer to placing the leading cars under tension to pull on the derailing cars, I am not saying that this will be an extraordinary high amount of pulling force. The tension that I am referring to would only function as a kind of preload tension ahead of the derailed cars to keep them from becoming an obstacle to the trailing cars pushing forward with their kinetic energy. What are going to do going downhill? The train will be using dynamic brakes which means it will be in compression. How are you going to create this tension and still stop the train going downhill?
Euclid When I refer to placing the leading cars under tension to pull on the derailing cars, I am not saying that this will be an extraordinary high amount of pulling force. The tension that I am referring to would only function as a kind of preload tension ahead of the derailed cars to keep them from becoming an obstacle to the trailing cars pushing forward with their kinetic energy.
When I refer to placing the leading cars under tension to pull on the derailing cars, I am not saying that this will be an extraordinary high amount of pulling force. The tension that I am referring to would only function as a kind of preload tension ahead of the derailed cars to keep them from becoming an obstacle to the trailing cars pushing forward with their kinetic energy.
What are going to do going downhill? The train will be using dynamic brakes which means it will be in compression. How are you going to create this tension and still stop the train going downhill?
If my system activated upon the occurrence of a derailment while the train was in dynamic braking, the system would have to take the engines out of dynamic braking. At the same time, it would apply considerable ECP braking to the cars behind the derailment; and somewhat less ECP braking to the cars ahead of the derailment. This differential braking would stretch the train, and focus that stretch on the cars involved in the derailing process.
dehusmanWhat are going to do going downhill? The train will be using dynamic brakes which means it will be in compression. How are you going to create this tension and still stop the train going downhill?
Well, first by law you're going to be under the speed restrictions applicable if you weren't using dynamic (particularly after the Seventeen Mile Grade problems!), and second, you're going to have the modulated brakes applied to hold the train appropriately.
All the automatic system does, when it detects a derailment (due to changes in vibration, or 'differential rotation' or whatever) is to modulate the braking behind the point or 'car' of detection to a slightly greater rate, enough to produce the differential tension across the coupling behind the derailment.
Now, the point you raise is nontrivial; when this system actuates, the amount of commanded dynamic becomes, more or less suddenly, highly excessive to 'requirements', and this may result in abrupt slowing down of the consist ahead of the point of derailment. So the effective amount of proportional braking needs to take this into account in order to keep the (smaller) amount of tension between that forward consist and the leading end of the derailed section.
I don't think that this is an insoluble, or even a particularly difficult, problem, given the existence of distributed strain gages or similar sensors in the draft gear. An emergent question is whether there should be some sort of distributed control, or modulation, of the dynamic brake control. I'm still a bit concerned about active traction control on automobiles, so this isn't as simple as Popular Science might have you believe... ;-}
daveklepperBut you have to solve the stringing on curve derailments problem and how you can solve that problem is behond my current comprehension. Also, what if the engineer knows there is worse danger ahead and only the quickest possible stop will avoid disaster?
There will not be any stringlining caused by this system. A key point that may not be clear is this:
In the absence of such tension, if the force of the leading cars and the trailing cars could be kept identical, there would be no tendency to jackknife the derailing cars. But I see this preloading tension as extra insurance against the possibility that the force of the leading and trailing cars might vary somewhat. If it varies in a way that the leading cars decelerate slightly quicker than the trailing cars, the system would fail its purpose. So the preload tension on the leading cars guards against that failure.
The tendency for stringlining increases with the sharpness of a curve and I don’t anticipate the tension applied by this system during a derailment to be great enough to stringline most mainline curves. The greater the speed, the lower the amount of extra tension that will be needed. And the lower the speed, the less need there will be for the anti-jacknifing system.
But beyond the natural unlikelihood of stringlining a curve will be the smart system control itself, which will prevent stringlining. I mentioned that my system would have a controller that would account for factors such as speed and tonnage. One other factor it would account for is location of the train on the line. This would tell it whether the train was rounding a curve or not. So the system controlling the application of tension would factor in the curve and limit tension if necessary to prevent stringlining.
But you have to solve the stringing on curve derailments problem and how you can solve that problem is behond my current comprehension. Also, what if the engineer knows there is worse danger ahead and only the quickest possible stop will avoid disaster?
EuclidI realized that the buffers would have to be exceptionally strong to serve the anti-jackknifing function. And it requires two buffers to serve one drawbar. So I decided to dispense with the buffers and rely solely on the fundamental anti-jackknifing feature of pulling on the train into the derailing cars.
I think both features are exceptionally important, and both are warranted far above the idea of trying to put substantial strength into the draft gear and drawbars, etc.
The differential proportional braking is important, and it will work as desired in many cases. There are many, many other cases, however, in which it won't. For those situations the 'buffer' anti-overrun devices will be important, particularly when you have enhanced methods of keeping the cars from separating physically. Even if one or two derailed cars 'get sideways', a method of keeping the cars behind that point physically aligned with the track direction is a positive aspect...
The immediate question is whether adding the appropriate reinforcement behind the buffer anti-overrun faces can be done effectively on a tank car, especially considering the increase in mass required in the tank structure alone due to the double shell. It is at least technically possible that the force can be carried smoothly into the outer shell with appropriate engineering, and some 'controlled crush' structure might prove practicable without necessarily puncturing the inner shell. I do think something better than pathetic little after-the-fact shields needs to be worked up...
I do recommend that you retain both design features in the proposals you make.
Thanks Dave and Overmod for being very understanding of my concerns. I agree that there is nothing wrong with anybody posting alternatives here to what I am proposing here. My only concern was about the possible appearance that there was just one proposal being discussed with a doubling of explanation, which would obscure both proposals.
I agree that any ideas such as these have to be shown to people in the industry to have any effect. And for such a showing, the concept has to be presented in the clearest manner possible. Communicating the details and purpose of an invention can be an enormous challenge. Sometimes a prototype or a model is beneficial to the explanation, but in the case of these railroad systems, a prototype is out of the question due to its size and cost. A physical model might be an option, but I would choose a diagram with illustrations and text callouts showing a sequence of events in the operation of the concept. Every word needs to be carefully chosen in order to get the most clarity for the fewest words.
Regarding your comments about the buffer system. I did indeed modify my proposal by removing the buffer system which was part of the original explanation on page one. In that original intent, the drawbars were made stronger to resist the added tension of pulling on the derailed cars. Then, I saw that this added tensile strength could be taken advantage of in preventing jackknifing. That would be accomplished by adding buffers, which would resist jackknifing by going into compression in reaction to the couplers going into tension.
However, in thinking about it, I realized that the buffers would have to be exceptionally strong to serve the anti-jackknifing function. And it requires two buffers to serve one drawbar. So I decided to dispense with the buffers and rely solely on the fundamental anti-jackknifing feature of pulling on the train into the derailing cars.
Euclid, I thak you and appreciate the suggesion. Again, I probably would not have thought through my ideas on this subject if you had not started the topic.
I thnk I have defined my proposal and its options pretty throoughly in past postings on this thread. I have presented the basic ideas to both EMD amd GE via email on their commens inpus on their website. If others have more to say one way or another concerning my damage control system thay can start a new thread and I will participate.
EuclidBut for the drawbars to play that role, the outer edges of the car ends must be reinforced to withstand the extreme compression that is the reaction force to the drawbar tensile load as the cars try to jackknife. This is the buffer system referred to in item #3. It would consist of extra strong corner block structures that would be spaced from one car to the next only far enough apart to allow the cars to traverse curves.
Stuff appears to be changing here since the version that was originally proposed. That is a good thing, in an important sense, because it shows that the design is evolving as difficulties are perceived. The problem is that if the original description is where the changes are made, it creates the impression -- correctly or inappropriately -- that the original inventor has predicted the 'ultimate' form of the system all along, rather than evolved things as concerns arose. Now I distinctly remember in the early phases of discussion about how the drawbars were going to be made strong enough to resist the jackknifing forces, and how the drawgear was going to have to be optimized to take the substantial forces The proposal as now written has much more reference to using appropriate devices and methods for the 'anti-jackknifing', and I would like to see some discussion now directed specifically at these aspects.
An important detail of the Miller passenger-car system was the provision of anticlimbers to prevent telescoping of the cars. This involved the invention of a device which could absorb far more energy than the couplings between cars could themselves sustain, even where there is an absence of flexible and elastic connections needed for trains to traverse normal curves and switches. A similar system is now proposed for the outer corners of the cars to help prevent jackknifing.
In a very simple form, what is required is a system of 'lateral anticlimbers' as far apart on the faces of the cars as possible, which would lock together if cars were pushed together and prevent further mutual rotation in yaw sufficient to separate couplers (or bend/break drawbar connections). This must be relatively fast-acting, as otherwise differential momentum effects alone may build up sufficient force to damage any connection between cars, no matter how robust. One thing to note is that the provision of some forms of longitudinal draft gear, per se, would no longer be anathema, and to an extent the mandatory use of drawbars the full length of the train is no longer critical to the design (the mutual "anti-jackknifing" and anti-roll devices between coupled ends can be different in type, size, and action from those within semipermanently-coupled 'rakes')
One immediate concern is that the mutual 'locking' has to be effective if there is more than just yaw 'misalignment' of the cars. Should a car roll during derailment, as we have discussed, it may come far enough out of loading gage as to foul an adjacent track. The system should, if possible, resist this tendency -- the 'catch' being that if the differential-braking method is being used, the compression alignment will not be effective in roll. There are ways around this -- and I think they should be brainstormed, not just analyzed -- but I do not think very strong (against twist) drawbars are a good solution in and of themselves.
Note that the forces acting to produce jackknifing need to be resisted early. For those of you that hate physics: think of the action of a hammer. If even a few inches of travel are required to engage a pair of 'corner anticlimbers', the force exerted with 'lever action' on the center-mounted draft gear will be highly magnified. This is different from the geometric considerations mentioned in the original description, and in my opinion ought to be noted specifically there. The use of fins or 'teeth' to interlock the two buffer blocks on adjacent cars, while important, will only slightly ameliorate the tension induced in the drawgear.
I am wondering whether some form of automatic extension of the corner blocks, or taking up of travel between cars, might be appropriate to provide -- without pyrotechnics! -- in the event of a derailment. In a simple system this might be provided (where ECP braking is being used) by the brake air supply, since pressure drop is no longer being utilized as the control signal. In the case of the 'buffer' blocks, they might be moved forward by spring to the 'forward' position, with some form of progressive tumbler dropping to provide the required very strong compression resistance without jamming the cars beyond ability to traverse curves... which I think would induce derailments directly if falsely or excessively deployed.
Likewise, something that pulls the cars more closely together when severe yaw moment is detected (in other words, jackknifing needs to be strongly resisted) might be provided. This wouldn't be a latch, but might involve some sort of positive limit stop that would act as a latch once a permissible amount of mutual yaw had been reached with progressive resistance. (This suggests another design refinement: that the buffer blocks be designed to provide a restoring moment to the 'upright and locked' alignment when pressed together, rather than just preventing further mutual displacement or roll when engaged. (I have no doubt that if this was not already in the original plan, it soon will be, to paraphrase Martial... ;-} ).
I think at this point Dave Klepper should start his own 'safe oil train' thread, clearly describing what his system involves and how it handles things like jackknifing and rolled-car clearance issues. So far, the operative principle appears to be stopping the train in an absolute minimum time while preventing either buff or draft shock to any part of the train, including the derailed cars. Those discussions are very different in nature from what is involved in the present proposal. I don't think any of the present posts in this thread regarding Dave's system should be edited (or removed), but going forward there should be a distinction between the two approaches in all appropriate senses.
Euclid, I agree that new ideas should have a forum and be discussed. I discussed what I see as problems with your idea in previous postings and need not repeat them. If you still have faith in your concept, by all means contact people in the industry that you think can implement them, as I have tried to do with mine. I'll post any responses that come my way and you can do the same. I probably would not have developed my scheme if I had not seen some issues with yours.
OvermodThe semantic question is that the thread is about 'safe oil trains' now... and not just the original system, at least some details of which have been essentially deprecated (like the bulletproof centersills and massive drawbars doing all the business).
Yes, new ideas attract deprecation. What fun would inventing be without the doubters? I once did some work for a company where they would assemble us into a big group to brainstorm how to introduce a new product that could be put on the market. But the human nature of the effort assured that there could be no new product that would work. Everybody shot down everyone else’s ideas until there were no ideas. And then we all moved on to the next challenge.
Often the deprecation here has depended on revising what I have said in order to make it less realistic for the purpose of facilitating the deprecation. For instance, I never said that I was proposing “bulletproof centersills and massive drawbars doing all the business,” as you say.
All I said was “extra strength solid drawbars and continuous extra heavy car center sills.”
It was others who immediately concluded that I was proposing making the drawbars so strong that their weight would increase by over 100 times. That way, they could say the idea would not work because by adding 100 tons to the drawbars, the car would not be able to carry the weight of the oil.
I also never said that the extra strength drawbars would be “doing all the business.” I only said they were one element of a system. The system relies on pulling into the derailment in order to stretch it out, and a parting of the train defeats that purpose.
So it makes sense to add some drawbar strength and coupling integrity to help resist the tension inherent with this system as it extends through derailing cars. But that objective is nothing new. Drawbars have been upgraded and improved several times for that same objective of making them stronger and less likely to uncouple during derailments.
The semantic question is that the thread is about 'safe oil trains' now... and not just the original system, at least some details of which have been essentially deprecated (like the bulletproof centersills and massive drawbars doing all the business).
The 'fork' occurred somewhere in the discussion of differential braking, where Dave decided to run with the idea of bringing the whole train to a halt quickly, and your approach went toward modulating the braking just so that tension across the presumably-derailed cars was optimized. I'd recommend establishing two new threads, one for magnetic emergency braking and one for differential braking as an adjunct to stopping derailed trains more effectively.
Euclid But to the question at hand: Is monitoring wheel rotation speed really the simplest way to detect a derailment?
But to the question at hand: Is monitoring wheel rotation speed really the simplest way to detect a derailment?
No, it's not; that's Dave Klepper's opinion. and it only makes sense to detect a derailment if you already need the rotary encoder(s) for another purpose. The wheels may continue to spin with considerable rotational inertia, or may continue to spin bumping over the ties (with the considerable 'adhesive' weight encouraging the transfer of energy into their rotation). If you design the system for 'slight' differences, you'll be back into the fun that occurs when wheels wear to different profiles and effective diameters.
If that method is used, I would think you would need to sense the rotation speed of every axle in the train, and compare that rotation rate to the average rotation rate of all the axles.
I wouldn't think so. Even comparing adjacent trucks would do the job, and that's a simple distributed function for 'smart cars' without their needing to know location in the train (as they would if differential braking were involved).
Why can’t you just sense the vibration on each truck and compare that to the normal vibration?
You can, and I've already said you can, and I've already said that I think this represents a 'better' idea for detecting derailments. My original device was intended to detect and record periodic vibrations that could be interpreted as flats or other wheel defects, but it is also capable of determining a number of other vibrations and moments that signal different types of failure (e.g. truck skew, bearing failure, and derailment) that require prompt attention. The device can use a number of modalities to keep itself charged, and to communicate with other equipment both on the train and in wayside or portable detectors. Etc.
Again, I am suggesting application only to uniform well-maintained trains, where braking effort can be uniform, ditto other railcar characteristics.
Wheels running on the ground have have flange diameter rotational speed. On rails it is tread diameter rotational speed.
Wheels on cars digging into the ground and thus just starting to jacknife, stop turning!
I even once witnessed a slow-speed drailment from trackside.
Euclid: YOu are making the matter much more compllicated than it is, Euclid. Any derailmen of any one car will definnitely and in all cases cause a difference in rotation speed between any two of the four axles of the car if both trucks leave the rails and between the axles of one truck that is the only truck t hat leaves the rails and between its axles and the axles of the truck still on the rails. Thus, with all cars reportiing to the locomotive and to the brake system, the moment any one truck leaaves the rails, the moment any one axle leaves the rails, emergency braking is implemented with the entineer simultaneously notified. It is a simple system, using existing componants, and it will work.
Using sensors requires a great deal of research, including experimental deraimens, testing to insure that hard coiuplings, low joints, switch points, frogs, insulated joints, don't register false deraklment notices.
And note that your differential braking may create a real hazard in a specific situation because the front of the train won't stop quickly enough where uniform fast braking would have avoided a hit. Also, magneting track brakes are difficult to apply differentially, and test may prove they do have value in stopping a train uniformly as fast as possible. Finally, the technology to prevent stringing with differential braking on curves still has to be developed.
DeH: I have seen movies of derailments and all have the characteristics I've assumed. The difference in rotational speeds that would trigger the derailment notice would be calculated to be larger than differences in speeds between wheels slipping on the inside rail vs. those slipping on the outside rail. Actually, although this situation is poasible and thus must be accomodated in the emergency system, in most cases the ouside wheels are running closer to the flange and thus at a larger diameter and circumpherence than the inner wheels (tapered wheel profiles) and slippage is minimized.
I happen to have two MIT engineering degrees, and although my practical onboard railroad expereicne was a long time ago, I did have such experience, plos doing all kinds of work at a trolley museum subsequently. I think I can make the kind of recommendations I am making with confidence that they will be successful if applied.
The kind of track brakes I'm recommending are the off-the-shelf variety used on light rail cars, modified to fit exactly mounting inside regular freight truck frames and with any lessons as appled to the Indiana High Speeds and C&LE high-speed cars. And the Inidana cars did operate mu, three in regular service, four in speical occasions.
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