OvermodWithout a full timeline of locomotive-control events starting probably at relevant CP passage, we can't have any particular rational discussion about who did what when.
The NTSB has not provided adequate information for a detailed sequence of events, but they have provided several markers with which one can fill in addional information. Like Sumwalt said, "You can do your own math." For instance, with speed and time before impact, one can determine distance. That should be reasonably accurate, given the relatively short intervals. Sumwalt's abbreviated timeline goes back 7 seconds prior to impact. That would seem to place it about 100-200 feet into the siding from the switch, depending on where the situplated 659 feet was measured from.
Cotton Belt MP104amen, and to add to the insensitivity of the subject there have been discussions/arguments about airlines customer service, getting drunk and playing wack a mole sad those who argue for argument sake let'em dry out in the wind = no resposce they tire when no counter argument is given endmrw0210181421
You know, some of us discussing the issues (and injecting silliness) are the same ones that run trains in dark territory. So, yes we understand the issues as it could happen to us.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
Beside question at which distance the misaligned switch was visible how early were the parked CSX locomotive visible?
Is it possible that the Amtrak crew realized the misaligned train, gave a three second horn signal to warn the people of a rough ride through the switch and only then recognized the CSX locomotive and applied the emergency brake?Regards, Volker
Well said, Electroliner.
_____________
"A stranger's just a friend you ain't met yet." --- Dave Gardner
When those of you who want to argue over how many verses you can engrave on a pin head get done, let us not forget that there are two men who died doing their job are dead and had about five seconds to realize that they were going to die. The rules are there because others before them have died. The rules allow operation of trains but require others to perform acts that keep the trains safe. If everyone had done their job according to the rules, Amtrak 91 would not be in the news. Unless this was deliberate sabotage, or vandalism, someone failed to follow the rules. This we will learn when the STB provides additional information. I for one ask that the nit picking over how far away an open switch can be observed and whether the engineer shoulda, woulda, coulda reacted faster, differently, or othe issues stop. It has become childish, repetative and meaningless. To some, it may be fun, but not to me. It reminds me of children arguing over who got the bigger piece of cake. Whether it would have been possible to see an open switch has no meaningful result. If you can see an improperly aligned switch, at a speed greater than about 20 mph (just a number I chose, you can but please don't pick another just for the sake of arguing) you still are not going to stop before going through it. And at higher speeds it is worse. So lets say prayers for those who have died and respect those who are operating the trains to the best of their ability. and follow the rules.
edblysardThe fastest an emergency brake application will occur is the speed of sound.
Not on Amtrak equipment, which activates the brakes on the train at about 93% of the speed of light. Setup to full cylinder pressure involves mass flow and of course is slower than 'sonic', but is still very quick on this equipment and occurs substantially in parallel.
I do not know directly what equipment is activated when the emergency button on a P42 is engaged; perhaps someone with appropriate technical information will provide it.
EuclidAs I said, I think 250 feet is a fair minimum, and it could be up to 500 feet or more. At night, an open switch shows a prominent black shadow in contrast to the headlight gleam on the rails. That shadow stands out because it diverges where the curved stock rail passes the open switch point. I have never measured the site distance, but on a railroad track, things look closer than they actually are.
I'm still curious where you gained this expereince from.
Another point that might be kept in mind is that braking 'curves' are the way they are because fixed braking effort, including full emergency, will produce higher relative deceleration at lower speeds. Good drivers recognize this directly as they slow for lights and stops; you can see it very dramatically in the video of the LRC near-collision (where, moreover, even a trained railroader misunderstands the closing deceleration rate).
So the effective speed, and hence momentum transfer, at the point of collision will be proportionally and not directly less with earlier reaction, which I think is the point Euclid is making. As I've said before, we need better data on the effective 'braking curve' of 91's consist on that track profile to make more than an educated guess about deceleration rate, and there are other factors that may be involved. But as Big Jim pointed out, you'd be surprised how fast you can come to a stop if you don't care about flat wheels, and much of the reduction of distance comes in the last seconds of time.
I think I have mentioned this before, but do not confuse the 'three seconds to recognize an open facing-point switch' with the 'three seconds from mushroom-button emergency to collision'. They are two completely different things.
Again, it may help to understand the sequence of events if you review the equipment on a P42. The 'blended braking' system is designed to make the shortest possible service stop when the lever is moved. The emergency control, which can't be disabled once pressed, applies full possible braking. Both systems drop the engine to an appropriate speed when selected; I would assume that they disable 'forward power' to the traction-motor control system almost immediately whether or not the prime mover is kept at higher speed for the dynamic part of blended braking. (I am assuming NTSB will show all this and not just 'throttle position' in their first informed report.)
Without a full timeline of locomotive-control events starting probably at relevant CP passage, we can't have any particular rational discussion about who did what when. It is particularly unfortunate that we will have so little understanding of what the engineer thought to do in this interval; it will mostly be from what we see on the inward-facing camera, and frankly I have little trust this will have actually produced meaningful results here; it certainly doesn't seem to have done so in Amtrak wrecks since 188.
As I said, I think 250 feet is a fair minimum, and it could be up to 500 feet or more. At night, an open switch shows a prominent black shadow in contrast to the headlight gleam on the rails. That shadow stands out because it diverges where the curved stock rail passes the open switch point. I have never measured the site distance, but on a railroad track, things look closer than they actually are.
Even in a curve, 250 feet is not going to bend very far, and is unlikely to cut off the view of the points.
I want to clarify something. Many times here, people have made the comment that you are not going to slow down much in 250 feet. Yes, ideally, the safest approch will allow you to stop before going into an open switch. But we are talking about braking in this particular collsion, and that involves the opjective of how much the train can be slowed in 909 feet.
As it was, the train slowed 6 mph in that distance; from 56 mph to 50 mph. Instead of going into emergency at 909 feet, it went into emergency at approximately 229 feet from the collision.
tree68 ruderunner so assuming passenger cars at roughly 85' werew looking at an 850 foot sight distance correct? Or if you're referring to 40' boxcars then 400'. Most freight folks these days think in terms of a 50 foot car, so that would put it around 500 feet, more or less. No one has questioned the 250' figure. Only how much braking can occur in the three seconds that would elapse between seeing a misaligned switch and then reaching it at near 60 MPH.
ruderunner so assuming passenger cars at roughly 85' werew looking at an 850 foot sight distance correct? Or if you're referring to 40' boxcars then 400'.
Most freight folks these days think in terms of a 50 foot car, so that would put it around 500 feet, more or less.
No one has questioned the 250' figure. Only how much braking can occur in the three seconds that would elapse between seeing a misaligned switch and then reaching it at near 60 MPH.
23 17 46 11
ruderunnerso assuming passenger cars at roughly 85' werew looking at an 850 foot sight distance correct? Or if you're referring to 40' boxcars then 400'.
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...
so assuming passenger cars at roughly 85' werew looking at an 850 foot sight distance correct?
Or if you're referring to 40' boxcars then 400'.
That gives the engineer significantly more time to react, still not enough to prevent the collision but enough to minimize the impact by a significant amount.
That doesn't account for the curve reducing the sight distance. One can do the math to determine the actual sight distance reduction due to the curve but at this point Euclid doesn't seem too far off with his 250' estimate.
Thanks for the actual answer Randy.
Larry, 100 yards is 300 feet, less than one carlength difference from the estimate.
Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction
ruderunnerY'all are spending the time to claim Euclid doesn't know what he's saying but I haven't seen any other estimates.
Sorry, I don't usually have a tape measure with me to verify how far I am from a switch when I can see the points.
Remember that the gap between the stock rail and the open points is only a couple of inches. If you're rolling down the railroad at speed it can be tough to see from any distance.
That said, I'd say a hundred yards or so. My eyes aren't as sharp as they used to be - although still well within the FRA requirements. Someone with "eagle eyes" might be able to spot it further out.
As for Bucky, he just admitted he likes to pull everyone's chain. I'll just leave that there.
Maybe 10 car lenghtx in the dark, 15-20 car lengths in day light
Saturnalia zugmann Euclid Just based on recollections of watching switch points. What is your estimate? When did you watch switch points? And from where? Apparently being an academic makes you an expert inquirer on any potential subject so long as you can ask a billion questions of and seek a billion possible solutions to problems that have no actual solution. Or, you could just listen to the actual authorities on these issues. We have legions of train operating folks on here and yet some ignore their experience and wisdom. Maybe, just maybe, we've found a case where academics will never know more than the people who do that job on a daily basis. But that won't ever stop them. It's tiring to read and detracts from the real discussion and insight that comes from listening to the people who actually DO THIS JOB. They're the authority on this issue, and way more worthwhile to listen to than those who seem hell-bent on ensuring the thread goes on forever with their propositions and academic reasoning. I'm no railroad operating man but I know enough and have heard enough listening to them that I bet a certain somebody here would probably be crapping their pants if they ever had to run a real freight or passenger train - when propositions are worthless and mistakes can kill.
zugmann Euclid Just based on recollections of watching switch points. What is your estimate? When did you watch switch points? And from where?
Euclid Just based on recollections of watching switch points. What is your estimate?
When did you watch switch points? And from where?
Apparently being an academic makes you an expert inquirer on any potential subject so long as you can ask a billion questions of and seek a billion possible solutions to problems that have no actual solution.
Or, you could just listen to the actual authorities on these issues. We have legions of train operating folks on here and yet some ignore their experience and wisdom.
Maybe, just maybe, we've found a case where academics will never know more than the people who do that job on a daily basis.
But that won't ever stop them. It's tiring to read and detracts from the real discussion and insight that comes from listening to the people who actually DO THIS JOB. They're the authority on this issue, and way more worthwhile to listen to than those who seem hell-bent on ensuring the thread goes on forever with their propositions and academic reasoning.
I'm no railroad operating man but I know enough and have heard enough listening to them that I bet a certain somebody here would probably be crapping their pants if they ever had to run a real freight or passenger train - when propositions are worthless and mistakes can kill.
So, what is a real world estimate of the sight distance?
Let's pretend for right now that this is straight level track, dark but clear. We can account for the curve from there.
Y'all are spending the time to claim Euclid doesn't know what he's saying but I haven't seen any other estimates
aother site says 91 & 92 / 10th will operate normal route. Guess that the 6 days of backup auto deliveries can start moving toward the site ?
I have railroad experience, some of it isn't very nice.
Electroliner 1935 zugmann Nah, not important. Nothing that would impress you. Hell it doesn't even impress me. I don't really consider myself an academic, tbh. Ahh, another EUCLID. I thought better of you.
zugmann Nah, not important. Nothing that would impress you. Hell it doesn't even impress me. I don't really consider myself an academic, tbh. Ahh, another EUCLID. I thought better of you.
Nah, not important. Nothing that would impress you. Hell it doesn't even impress me. I don't really consider myself an academic, tbh.
Ahh, another EUCLID. I thought better of you.
At least Zug can use the forum software properly when quoting people. Just sayin
Greetings from Alberta
-an Articulate Malcontent
Electroliner 1935Ahh, another EUCLID. I thought better of you.
Ahh - but there is a difference - Zug has bona fide railroad experience.
I've got two associates degrees - they're in a drawer, too (or are they in the cupboard over the closet?). But I also hold a railroad engineer's card, which is far more relevant here.
Think what you want. I don't care.
zugmann It's in a drawer. Q Clever will get you many places. What discipline and from what College, please. I wish I could learn more about Bucky but he does not want to tells anything about himself
It's in a drawer.
Q
Clever will get you many places. What discipline and from what College, please. I wish I could learn more about Bucky but he does not want to tells anything about himself
zugmannIt's in a drawer.
Electroliner 1935In?
a drawer.
zugmannI don't know what your definition of "academic" is, but I do have a college degree.
In?
EuclidI don't think zugmann is an acedemic.
Gonnna insult my mother too, while you're at it? Go right ahead - she's dead and won't mind.
I don't know what your definition of "academic" is, but I do have a college degree.
I don't think zugmann is an acedemic.
Streak, we're likely going to have to wait for the next preliminary NTSB report to know any of that in a reasonable way. About the only thing that is indisputably clear is the EO 24 violation, because overt events confirm it. That is far from 'explaining' what happened, though -- and we need the detailed results of the interviews, or an intelligent synopsis of them, before we can do anything more than rank supposition.
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