Midland: Thanks for the lesson. Now what happens if say one in ten thousand cars is not properly filled and has more empty space ?
blue streak 1 Midland: Thanks for the lesson. Now what happens if say one in ten thousand cars is not properly filled and has more empty space ?
Yes but ......
Never too old to have a happy childhood!
Dave H. Painted side goes up. My website : wnbranch.com
schlimm Midland Mike: Thanks for the cogent application of wave motion to an oil tank car by an expert who is clear about his background.
Midland Mike: Thanks for the cogent application of wave motion to an oil tank car by an expert who is clear about his background.
Some intuition of what's happening in a tank car can be gained by filling a bottle 97% full with water, capping the bottle, laying it in its side and shaking it horizontally. Chances are you won't be able to feel the effects of sloshing. A half full bottle is another matter...
I remember using the sloshing trick to estimate how full the bottle of milk I was pulling out of the fridge - the bottles were made of very dark brown glass and it was difficult to gauge the level by eye. The same trick is also useful for 20 lb propane tanks for the BBQ, if it feels light and can't sense a sloshing inside, then it's close to empty.
erikemI remember using the sloshing trick to estimate how full the bottle of milk I was pulling out of the fridge - the bottles were made of very dark brown glass
I remember milk bottles and jugs being clear with the milk comany's name printed on the outside. Brown or green glass must have been rare, mostly used for beer or some pop brands.
C&NW, CA&E, MILW, CGW and IC fan
In a 97% full tank car, the wave amplitude is limited to 8" by the headspace. In a half full car, you could potentially have a 5 ft amplitude, however, to get that 5' wave above the 5'static level at the front of the car, the back end of the car would have to have 0 depth of oil, and I just don't think that would happen in a brake application. Even then only 3/4 of a full static load (for the front half of the car) would be over the front truck. And any kinetic load would slowly build up as the wave swell built up against the front of the car and disipated, so I doubt there would ever be a time when the front truck was overloaded. Anyway, we are talking about the effects of 100 car loaded trains causing repetative stress, so one odd car is not going to do much. Also, I would think that an improperly filled tank car would not be unique to oil loads.
schlimmYour subtext is that you set yourself up as more expert than the Canadian investigators who wrote the reports referred to in the article. If the report is produced, then you "will read it, see if it contains data on the specific forces and/or presumed mechanisms of action, and request information from the appropriate people or other entities if not." I am not an expert on this and do not pretend to be. But what are your credentials to disregard the preliminary conclusions of the safety board? What are Husman's?
I specifically deny that I am "more expert" than the Canadians -- and I am not sure exactly how you have misconstrued what I said so badly. In the past three pages or so of the thread, we have seen allegations by multiple posters that at least one of the reports conflates unit-train results with oil unit trains specifically, and this may make it unclear at best that any characteristic of the oil lading -- including slosh -- is actually contributing to the supposed increased track damage. On the other hand, the paragraph from the report, which has been repeatedly quoted, indicates that the Canadians say, or think they can say, that some aspect of oil traffic itself is contributing to the finding of track defects.
Let me repeat, in different words, that I would like a link to the actual cites of the reports so I can read them and determine if there is actual data or discussion of specific oil-related causation in them. And then, if there is not, or if I think it is possible that, as others have said, unit-train behavior has been somehow conflated with oil-train behavior, I can e-mail the TSB or one or more of the authors, and humbly request clarification from them.
If I were setting myself up as an expert, I'd just advance hypotheses about what was being left out. I'm not going to speculate until I have seen for myself what is actually in the report(s) and ensured with the agency responsible that I have not misread or misunderstood any part of the report(s). Do you have an alternate methodology for researching something like this that you consider superior? If so, for heaven's sake lay it out in detail so I can learn from it and then follow it.
EuclidThe vertical separation of the oil from the air simply means the oil has moved forward as far as possible. When that happens, the trailing surface of the oil is vertical. In normal running the separation between the oil and air is horizontal. I am describing a process of load shifting due to extreme slack run-in such as the degree of run-in that might stand a car up or buckle the train sideways. Perhaps the load shifting of oil can contribute an additional destructive element sufficient to cause a derailment in cases of hard run-in that would that would be insufficient to cause a derailment if there was no load shifting.
Let me be real clear that I mean a car with the usual 'full' load of oil, and not a car that is only partially full, or containing a fluid with higher density or lower effective viscosity than something like Bakken or Eagle Ford crude.
There are very substantial differences between fluid mechanics and solid ones in some respects. You seem to be thinking that inertia in a fluid load will make it 'slide' forward in one slug, deforming a bit at the front to fill up the void space, and breaking loose and pulling away from the rear head as if the tank were vertical and the 'bottom' head abruptly removed. That is not at all how it behaves. Of course a substantial amount of the momentum of the oil is transmitted to the front head of the tank in a 'crash stop' of the car. But the only part of the oil that actually moves relative to the car structure is either 'pumped up' vertically against gravity, or slides forward (damped by intermolecularforces that manifest as viscosity) so that the horizontal 'plane' of the oil/air interface at the top of the car 'tilts' forward, to become 'normal' (meaning at right angles) to the resultant of gravity and the decelerative force. Inertia in that mass of fluid will not permit the angle to become the 90 degrees you think for a considerable time even if the effective deceleration is many g. (And as you will recognize, there is no way a multiple-g deceleration from normal oil-train speed can be protracted for any substantial time, whether or not you have lots of cars shoving 'out back'... set the equations up and you'll see why).
I do not need a PE or a degree in physics to know that slosh in the volume bounded by the arc with an 8" chord at the top of a tank car is unlikely to bottom side bearings, much less cause a three-piece truck to tip over. I would be surprised if there were even a chance for the force involved to set up significant enough harmonic rock (but I leave it to the experts to calculate that for sure, as I don't know for example if the snubbing effect is enough at the likely range of oscillation period.)
If the car were substantially less full, you might see some dramatic effects indeed from 'stopping it short', especially with no baffles. But the chance of an oil train operating with multiple cars in that state would be very slight, and I have not seen any report or discussion that says a derailment or other oil-train accident was proximately caused by a partly-loaded car in an otherwise fully-loaded consist.
I remain waiting for a technical discussion from the Canadian sources about the specific forces from the oil trains that 'find' the track weaknesses.
Having the TSB reports would be good but not really necessary. They are written by credentialed experts and by your own admission you are not. Yet you need to examine/review them before you can simply accept them. That clearly implies your need to put your stamp of approval or rejection on them, as though you were in a position to make a judgment. This sentence says it all: "and determine if there is actual data or discussion of specific oil-related causation in them. And then, if there is not, or if I think it is possible that, as others have said, unit-train behavior has been somehow conflated with oil-train behavior, I can e-mail the TSB or one or more of the authors, and humbly request clarification from them."
The TSB authors have drawn hypotheses/conclusions from data. Although there could be alternative hypotheses or data conflated, it seems to me that neither you (or possibly several others whose credentials are missing) who dismiss or minimize those conclusions are in a position to do so, based on a lack of expertise from training and experience.
The argument isn't what anyone is or isn't 'qualified' to be doing with data. It's about seeing the damn data in the first place. The original article that started this thread referenced a quote from the 'Safety Transportation Board Canada' or some similar garbling that tells me the reporter wasn't familiar with his sources, and although I have repeatedly asked here what the actual TSB report was, I seem to be getting little actual, helpful information about it. (I cannot find anything on the TSB's Web site that contains the quoted comment, and the last listed discussion of main-line derailment causes there is dated 1994.)
Argument from authority is a known logical fallacy, yet here you repeatedly, and insultingly, invoke it. Needlessly, I might add.
And while we're here, you said:
it seems to me that neither you (or possibly several others whose credentials are missing) who dismiss or minimize those conclusions are in a position to do so, based on a lack of expertise from training and experience.
And your credentials based on expertise from training and experience in track mechanics, vehicle design, or similar fields is ... what, precisely? It would have to be substantial for you to criticize someone like Dave Husman on such a basis ... but your credentials in that area also seem to be missing. Perhaps you will fill us in.
Meanwhile, for those who are more civil or concerned more with intellectual pursuits than preservation of academic prerogatives -- what's the ID for the TSB document that contains the quote referenced in the LA Times article? What's the functional equivalent of the Batlight for wanswheel?
Thank you.
schlimmAlthough there could be alternative hypotheses or data conflated, it seems to me that neither you (or possibly several others whose credentials are missing) who dismiss or minimize those conclusions are in a position to do so, based on a lack of expertise from training and experience.
Unless you are planning on offering me a job, I see no need to post a resume'.
wanswheelhttp://www.tsb.gc.ca/eng/enquetes-investigations/rail/2015/r15h0021/r15h0021.asp Preliminary indications are that track infrastructure failures may have played a role in each of the Gogama accidents and a 3rd accident that involved a mixed manifest train on the Ruel Subdivision near Minnipuka, Ontario on 5 March 2015. Petroleum crude oil unit trains transporting heavily-loaded tank cars will tend to impart higher than usual forces to the track infrastructure during their operation. These higher forces expose any weaknesses that may be present in the track structure, making the track more susceptible to failure…
And that's basically what everybody with railroad experience has been saying all along in this thread. Unit trains wear out track faster than non-unit trains. Unit trains stress the track more so they are more likely to find the defects. This is not exactly front page news in the railroad industry. Its been known for many years.
dehusmanAnd that's basically what everybody with railroad experience has been saying all along in this thread. Unit trains wear out track faster than non-unit trains.
Wizlish The argument isn't what anyone is or isn't 'qualified' to be doing with data. It's about seeing the damn data in the first place. The original article that started this thread referenced a quote from the 'Safety Transportation Board Canada' or some similar garbling that tells me the reporter wasn't familiar with his sources, and although I have repeatedly asked here what the actual TSB report was, I seem to be getting little actual, helpful information about it. (I cannot find anything on the TSB's Web site that contains the quoted comment, and the last listed discussion of main-line derailment causes there is dated 1994.) Argument from authority is a known logical fallacy, yet here you repeatedly, and insultingly, invoke it. Needlessly, I might add. And while we're here, you said: it seems to me that neither you (or possibly several others whose credentials are missing) who dismiss or minimize those conclusions are in a position to do so, based on a lack of expertise from training and experience. And your credentials based on expertise from training and experience in track mechanics, vehicle design, or similar fields is ... what, precisely? It would have to be substantial for you to criticize someone like Dave Husman on such a basis ... but your credentials in that area also seem to be missing. Perhaps you will fill us in. Meanwhile, for those who are more civil or concerned more with intellectual pursuits than preservation of academic prerogatives -- what's the ID for the TSB document that contains the quote referenced in the LA Times article? What's the functional equivalent of the Batlight for wanswheel?
1. I have never pretended to speak as having any credentials in those fields. I only cited omments of th TSB, whose investigators do. My background is well known to old-timers on here, but for young folks, it's a professor emeritus of clinical psychology and still practicing clinical psychologist. Midland Mike has years of experience in the petroleum industry. I feel no need to hide background, although you and husman have done so.
2. You confuse "appeal to authority" with simply choosing to believe experts in the field rather than the rather arrogant challenges to their report you make. Demanding to see not only the report but also the data before you would deign to expreess your approval is not the way things are done. For you to examine research data, you need to have the minimum credentials to be capapble of interpreting them in any meanngful way. And thus far, you have ont shown that you do.
3. Posters who previously turned Euclidian cartwheels to not endorse the opinions of the TSB now seem to be saying in Orwellian Newspeak, "Oh, sure. Unit trains produce greater stress on tracks, especially oil unit trains." I wonder what took them so long?
4. I have nothing else to add other than being civil does not preclude disagreement. Knowing what one does not know is one of the advantages of formal higher education as well as gaining a real depth of knowledge.
Euclid dehusman And that's basically what everybody with railroad experience has been saying all along in this thread. Unit trains wear out track faster than non-unit trains. It does not say that at all.
dehusman And that's basically what everybody with railroad experience has been saying all along in this thread. Unit trains wear out track faster than non-unit trains.
Wizlish Euclid dehusman And that's basically what everybody with railroad experience has been saying all along in this thread. Unit trains wear out track faster than non-unit trains. It does not say that at all. Can we please dispense with the semantics? What the language said was that heavier unit trains tend to 'find' defects in track structure more readily.
It does not say that heavier unit trains tend to find defects more readily. Rather, it specifically cites "petroleum crude oil unit trains." It makes no mention of unit trains in general. This is not a matter of semantics.
schlimm1. I have never pretended to speak as having any credentials in those fields. I only cited comments of th TSB, whose investigators do.
OK, we'll take that as a 'none' by your standards, then. Why then are you conducting ad hominem attacks on people who, for example, think the issue is a matter more of semantics than engineering, but want to confirm that?
My background is well known to old-timers on here, but for young folks, it's a professor emeritus of clinical psychology and still practicing clinical psychologist. Midland Mike has years of experience in the petroleum industry. I feel no need to hide background, although you and husman have done so.
And I have supposedly done so how? My background is well-known to you. I do think Dave Husman would do better to provide a brief statement of his experience and qualifications, but that's up to him.
2. You confuse "appeal to authority" with simply choosing to believe experts in the field rather than the rather arrogant challenges to their report you make.[/quote]
No, I confuse nothing. This isn't about 'believing experts' -- I doubt you have talked to Mr. Fowler or anyone else in the TSB qualified to discuss this. It's about mistaking the semantics in a public report for expert opinion, which is a completely different thing, and then acting arrogantly to chastise people who have not made that mistake as completely.
to see not only the report but also the data before you would deign to express your approval is not the way things are done.
This isn't about 'my approval' except in your imagination. It's about whether oil unit trains might cause more track damage than other kinds of unit trains, ceteris paribus. Frankly, you have no idea whether or not any expert has actually claimed this or not, but you are certainly ready to claim they have and to disparage anyone without equivalent expert credentials, again in the total absence of any reasonable kind of scientific or engineering proof, only the perhaps-incidental datum that experts participated in the formulation of the TSB report.
For you to examine research data, you need to have the minimum credentials to be capapble of interpreting them in any meanngful way. And thus far, you have ont shown that you do.
I understand English. I understand to the required extent physics and metallurgy. I understand how to look at evidence and draw reasonable conclusions. I know not to think that because an ambiguous statement might have originated from a PE it must mean what you want it to.
This is not a situation where refined statistics or recursion analysis is necessary to extract theories from a mass of data. This is not a situation where arcane knowledge or special training gives 'experts' an insight that even ordinarily intelligent people cannot share. This should certainly not be a situation where statements should be accepted without question simply because of their origin ... there's a name for that ... without having at least some form of proof or explanation attached to them.
Well, that isn't Newspeak for one thing, and for another -- I have to thread through your morass of an opinion carefully -- you will need to be more precise on which poster(s) who previously refused to acknowledge the TSB's claim are now saying, specifically, that there is 'especially' a problem with oil unit trains over otherwise-similar unit trains of other kinds. While you are doing that, please be clear on what those specific posters indicate that 'especial' problem is -- because that bears directly on the original issue.
4. I have nothing else to add other than being civil does not preclude disagreement.
That is very true. What you might do well to observe, though, is that disagreement should not preclude civility.
EuclidIt does not say that heavier unit trains tend to find defects more readily. Rather, it specifically cites "petroleum crude oil unit trains." It makes no mention of unit trains in general. This is not a matter of semantics.
The issue of semantics is precisely whether the additional qualifier of 'petroleum crude oil' is required to explain the additional track damage. If I understand correctly, the only unit trains on the line in question were oil trains, so there would be no basis of comparison there to distinguish oil unit train behavior from other unit train behavior. My personal suspicion, which of course is worth nothing by itself, is that the added words are a kind of boilerplate, included as a qualifier rather than a claim that the oil is doing something in and of itself that contributes to 'finding defects in the track' and exacerbating them to the point of failure. As I have said, I will be delighted ... if 'delighted' is an appropriate word to use in this context ... to find out actual causes of 'oil-induced' track damage where they exist.
Note that the derailment in the TSB report occurred under the sixth car in the train. Again not speaking as an expert, I wonder if many of the 'usual suspect' causes attributed to an increased propensity for unit trains to induce track failure would apply that early in a train's passage.
I think something else needs to be clear: we're talking about whether oil unit trains induce track damage in their normal running, not whether slosh or inertia or anything else causes greater damage after the derailment has started. While that in itself is (and has been!) a lively source of discussion, it should not be applied here. (And this also implies that we have to try to distinguish track damage or defects causing an accident from track damage occurring later in the accident -- which is not something I am qualified to determine, but which I do understand to be difficult and perhaps impossible to determine or divine in many incidents)
[I apologize here for any strange or transient formatting. The 'new' Firefox and Windows 10 are not at all doing well -- spaces don't register; clicking even one character away from text in a paragraph autoselects it (and then lags on deselecting it; every few minutes the browser 'freezes' randomly for some internal reason (other running programs or applications are unaffected, so I don't think it's an OS or hardware issue directly); occasionally a number of typed characters (for example when making a Google search) just 'disappear' (something is there, as white characters that can be backspaced out, but Google doesn't recognize them). Wish I could still say 'I'd rather have a Mac']
Euclid Wizlish, I certainly agree that it is possible that the TSB quote means to say something other than what the words say.
Thanks to Chris / CopCarSS for my avatar.
“Petroleum crude oil unit trains transporting heavily loaded tank cars will tend to impart higher than usual forces to the track infrastructure during their operation,” the safety board said in a report this year. “These higher forces expose any weaknesses that may be present in the track structure, making the track more susceptible to failure.”
There is nothing ambiguous about that nor is it about semantics.
Euclid It has taken many readings to come to that conclusion, but now that I have, I dismiss the article as offering nothing.
No,wait, don't do that!
When you come across something like this, take the time to research it more deeply if you can, and find out more about what's going on.
For instance: I am reasonably sure that a request to the TSB (or to Mr. Fowler) on this specific point would establish just what they meant.
(I might add that if you were to get a 'boilerplate' form response, or political Newspeak about the danger of oil trains in general, etc., that would tell you something useful, too.)
I happen to agree with Leonardo da Vinci that you can never 'trust authority' without at least trying to confirm the objective facts for yourself. As schlimm has pointed out very well, it is inappropriate and perhaps dangerous to substitute one unfounded opinion for another, or to reject a well-reasoned opinion by an 'expert' in a particular field -- there are many other caveats about this that I won't mention -- and it is likewise often self-defeating to begin speculating in the absence of good facts or data. (Again as schlimm points out, you need to have reasonably proven data, and know how to use and not abuse them, before you actually assert or claim something as true; there are less stringent but still important considerations when claiming something as false or unjustified.
I am still not sure whether it is justified to claim something is false just because 'it hasn't been satisfactorily proven yet, but experts are reported as saying it is' [edit: quote marks added because that sentence was highly ambiguous without them!] Leonardo tells you to learn enough to understand what they do, then test or check it appropriately. He only mentions by example that you can win an argument inappropriately, by any number of means, whether or not the facts subsequently prove or indicate quite otherwise...
It's the truth that should matter, not the argument. Even on Internet forums... Even if you dismiss the L.A.Times article itself, or even if you decide to accept the sentences in the TSB report as referring to 'heavier trains finding more damage', you should still look carefully, in the right places following a 'right' process, to see whether there are things about oil unit trains that make them more damaging to track than other types of unit trains.
There remains the reported (and to me, seemingly quite high) percentage of additional derailment incidence for unit oil-train consists compared to other trains. Whether or not I fully understand the statistical methods used, I would like to see someone with the right skills analyze that report and the data behind it, and perhaps at least start us in the direction of identifying any potential causative factors or other explanations behind the observation.
Questioning whether individuals have the credentials to dispute expert opinion rationally (of course, you can reject the report or hold another opinion, but notbas a disputation) is not an (argumentum) ad hominem, as that would entail a personal attack on your character or motive. As far as I know, the personal characteristics of forum members are beyond reproach.
schlimm“Petroleum crude oil unit trains transporting heavily loaded tank cars will tend to impart higher than usual forces to the track infrastructure during their operation,” the safety board said in a report this year. “These higher forces expose any weaknesses that may be present in the track structure, making the track more susceptible to failure.” There is nothing ambiguous about that nor is it about semantics.
I suspect you were about to make a point about Euclid saying this, but it got lost.
But before I read your actual comment, there is at least one very substantial ambiguity in the statement itself, one which is also related to semantics: what is "higher than usual" supposed to refer to? Other petroleum crude oil trains that have less-heavily-loaded tank cars? Other 'usual' kinds of unit train? The 'usual' sort of train on the line in question?
And this is at the heart of what we are supposedly discussing.
I am quite certain the TSB folks know what they meant, and will confirm the intended meaning when they are asked. But you cannot tell what the 'reference' force level is from that statement as written. Which was one of the original points.
schlimmQuestioning whether individuals have the credentials to dispute expert opinion rationally (of course, you can reject the report or hold another opinion, but not as a disputation) is not an (argumentum) ad hominem, as that would entail a personal attack on your character or motive.
As you well know, one version of argumentum ad hominem (it is also one of the better red-herring techniques) is to disparage the personal merits or qualifications of a person, rather than responding to the substantive merits (or lack of merits) of their opinions. That specifically applies to many of the insulting terms you have used in recent posts, and no attempt at pretending 'character' or 'motive' is 'above reproach' either justifies or excuses that.
You continue with the garbage claim that I am 'disputing' expert commentary in the report, when the discussion is about the words they used, or thatthey have made a statement a particular way. [Edited to clarify meaning]. I do not consider that I have disputed anything in this thread so far 'irrationally', although for sufficiently constrained or technical definitions of 'rationality' made outside the bounds of rational discourse, you might be able to make yourself believe so.
This whole line of argument has little to do with anything substantive on this thread, and probably on the open forum itself. It should have been taken to PM when it first came up, instead of being spieled to establish your street cred as an academic intellectual (which status needs no defense here in the first place)
I believe it was the English scientist Lord Kelvin (William Thomsen) who said that: "You start to understand a thing when you can describe it qualitatively [i.e., with words], but you really understand it when you can quantify it [i.e., with numbers]."
With such tentative words and phrases being used, as "tend to impart higher than usual forces" and "higher forces expose any weaknesses that may be present in the track structure, making the track more susceptible", this isn't even to the point of having a qualitative description to work from.
- Paul North.
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