7j43k, I got this site up on Google Earth and it seems the original curve has been modified to a less sharper curve from the original construction; but does not appear to be recent. Visually my eye says the train had exited the curve before derailing. But of course there may be a different analysis by the NTSB inspection.
Lithonia OperatorI don't get it. It says the engineer waited about 15 seconds (after going into emergency) before pinging the EOT. It was a forty-car train, and I would have thought that the entire train would have been at full braking within about five seconds after going into emergency in the cab. Not so?
I don't understand that either. My understanding is that a brake application propagates through the train at about the speed of sound. And each car has a vent valve to help speed the propagation of an emergency application through the train. So the last car should have been emergency long before 15 seconds, even on a relatively long consist like the Auto-Train. We don't use EOT on our RR, so maybe there is something there I am not aware of.
With that small of a train, you probably couldn't even get your hand from the automatic brake handle to the EOT dump switch before the rear end was at 0.
Now hitting it is a good reflex (just in case something got crimped off), but I think the NTSB was really reaching on that one.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
adkrr64Lithonia Operator I don't get it. It says the engineer waited about 15 seconds (after going into emergency) before pinging the EOT. It was a forty-car train, and I would have thought that the entire train would have been at full braking within about five seconds after going into emergency in the cab. Not so? I don't understand that either. My understanding is that a brake application propagates through the train at about the speed of sound. And each car has a vent valve to help speed the propagation of an emergency application through the train. So the last car should have been emergency long before 15 seconds, even on a relatively long consist like the Auto-Train. We don't use EOT on our RR, so maybe there is something there I am not aware of.
I don't get it. It says the engineer waited about 15 seconds (after going into emergency) before pinging the EOT. It was a forty-car train, and I would have thought that the entire train would have been at full braking within about five seconds after going into emergency in the cab. Not so?
Facts are Facts.
According to the event recorder information, the engineer initiated a service brake application at 5:07:57 p.m. He initiated an emergency brake application at the head end of the train at 5:08:01 p.m. By 5:08:02 p.m., the trainline pressure at the head of the train was 98 psi, the rear-end trainline pressure was 108 psi, and the train speed was 55 mph. At 5:08:04 p.m., the trainline pressure at the head of the train was zero and the rear-end trainline pressure was 108 psi. At 5:08:05 p.m., the pressure at the rear of the train dropped 2 psi to 106 psi and remained at 106 psi for 7 seconds. At 5:08:11 p.m., the EOT went into emergency. The trainline pressure at the rear end dropped to zero at 5:08:12 p.m. At 5:08:15, the engineer activated the EOT device. (See appendix E for more detailed event recorder information.
And after reading the Autotrain report, I looks very much like a similar case except the track failure may have occurred after the engines pased over it. Has any loco video been released?
Electroliner 1935 adkrr64 Lithonia Operator I don't get it. It says the engineer waited about 15 seconds (after going into emergency) before pinging the EOT. It was a forty-car train, and I would have thought that the entire train would have been at full braking within about five seconds after going into emergency in the cab. Not so? I don't understand that either. My understanding is that a brake application propagates through the train at about the speed of sound. And each car has a vent valve to help speed the propagation of an emergency application through the train. So the last car should have been emergency long before 15 seconds, even on a relatively long consist like the Auto-Train. We don't use EOT on our RR, so maybe there is something there I am not aware of. Facts are Facts. According to the event recorder information, the engineer initiated a service brake application at 5:07:57 p.m. He initiated an emergency brake application at the head end of the train at 5:08:01 p.m. By 5:08:02 p.m., the trainline pressure at the head of the train was 98 psi, the rear-end trainline pressure was 108 psi, and the train speed was 55 mph. At 5:08:04 p.m., the trainline pressure at the head of the train was zero and the rear-end trainline pressure was 108 psi. At 5:08:05 p.m., the pressure at the rear of the train dropped 2 psi to 106 psi and remained at 106 psi for 7 seconds. At 5:08:11 p.m., the EOT went into emergency. The trainline pressure at the rear end dropped to zero at 5:08:12 p.m. At 5:08:15, the engineer activated the EOT device. (See appendix E for more detailed event recorder information. And after reading the Autotrain report, I looks very much like a similar case except the track failure may have occurred after the engines pased over it. Has any loco video been released?
adkrr64 Lithonia Operator I don't get it. It says the engineer waited about 15 seconds (after going into emergency) before pinging the EOT. It was a forty-car train, and I would have thought that the entire train would have been at full braking within about five seconds after going into emergency in the cab. Not so? I don't understand that either. My understanding is that a brake application propagates through the train at about the speed of sound. And each car has a vent valve to help speed the propagation of an emergency application through the train. So the last car should have been emergency long before 15 seconds, even on a relatively long consist like the Auto-Train. We don't use EOT on our RR, so maybe there is something there I am not aware of.
So one has to wonder: why not simply wire it so that when you go into emergency it pings the EOT? How hard would that be? When would you not want the EOT to dump simultaneously?
I never would have dreamed that it would take ten seconds for a forty-car train to fully go into emergency. But given that, with both ends dumping simultaneously, I guess it would have taken five seconds to get the job done. Right?
Then you have to wonder: if the train stopped twice as suddenly, what kind of accidents would have been caused by that in itself?
Still in training.
Passenger brakes on the passenger cars. Lousy tread brakes and probably no graduated release on a great many top-heavy car-carrying freight cars. We have those here who can tell what braking a train like that under emergency conditions,
Electroliner 1935p.m., the trainline pressure at the head of the train was 98 psi, the rear-end trainline pressure was 108 psi, and the train speed was 55 mph. At 5:08:04 p.m., the trainline pressure at the head of the train was zero and the rear-end trainline pressure was 108 psi. At 5:08:05 p.m., the pressure at the rear of the train dropped 2 psi to 106 psi and remained at 106 psi for 7 seconds. At 5:08:11 p.m., the EOT went into emergency. The trainline pressure at the rear end dropped to zero at 5:08:12 p.m. At 5:08:15, the engineer activated the EOT device. (See appendix E for more detailed event recorder information.
You ahve to remember - what the head end is reporting is not always what the EOT is actually at. Sometimes there's delay or even non-communication between the two. So the rear end may have been already at zero before it showed as zero on the head end. Just going by what the head end says isn't always 100% accurate.
7j43kI did read a lot of it, and it is fascinating.
As I said in my first post on this thread, some of those reports are very educational, and I think that this one (RAR0302) is near the top of the list in that category. It reminded me of some of the Henry Petroski books of engineering history.
Both straight track and curved track can convert the sun kink rail stress into sideways relief. Sideways relief from either straight or curved track can derail the train if the relief disruption is large enough.
The relief causing track misalignment can occur either before a train reaches the track heat stress zone, or it can be initiated when the train enters the zone.
There is no specific ambient temperature threshold above which heat or sun kinks occur because while ambient temperature contributes to the cause, it is not the only contributing factor.
From this link:
https://www.whsv.com/2021/09/27/safety-officials-seek-answers-deadly-amtrak-derailment/
Temperatures were in the high 80s Saturday near Joplin, according to the National Weather Service.
Russ Quimby, a former rail-accident investigator for the NTSB, said heat is the most likely explanation. He is convinced because the locomotives in front did not derail, but eight lighter coach cars behind them did.
“This has all the earmarks of a track buckle also,” Quimby said. “Sometimes a locomotive, which is heavier, will make it through” a buckled track, “but the cars following won’t. You saw that in this accident,” he said.
And what did Russ say when asked why this didn't happen several weeks earlier, when the temperature was 12 degrees higher?
And how did Russ know it was heat caused instead of a failure in track/roadbed installation?
Ed
7j43k And what did Russ say when asked why this didn't happen several weeks earlier, when the temperature was 12 degrees higher? And how did Russ know it was heat caused instead of a failure in track/roadbed installation? Ed
As I have mentioned, sun kinks do not just occur when ambient temperature reaches a certain point. You can’t rule out a sun kink just because temperatures have been higher and no sun kink occurred.
What Mr. Quimby and I are saying is that a sun kink may or may not have been the cause, but that circumstantial evidence points to a sun kink as the cause. Mr. Quimby cites evidence for a sun kink derailment in that the locomotives in front did not derail, but eight lighter coach cars behind them did.
As I have mentioned, sun kinks not yet apparent have a tendency to be triggered into actual track misalignment as the train proceeds over the heat overstressed track zone. This is often results in the locomotive not derailing because it never encounters misaligned track.
Instead, it creates misaligned track trailing out behind the locomotive. Also, if track is misaligned before the locomotive reaches it, it may make it across safely because it is heavier than the trailing cars and thus it can hold the track better. In either case, the misalignment is likely to grow larger as the train passes through the danger zone.
However you seem to be positively asserting that a sun kink was not the cause. How can you be so sure?
In the picture from overhead, the rails nearest the three rear cars are bowed apart. Does that add to the sun link theory (stress relief)? North rail bowed North and South bowed South.
Euclid 7j43k And what did Russ say when asked why this didn't happen several weeks earlier, when the temperature was 12 degrees higher? And how did Russ know it was heat caused instead of a failure in track/roadbed installation? Ed However you seem to be positively asserting that a sun kink was not the cause. How can you be so sure?
I'm guessing nobody asked Russ those questions.
I'm not positively asserting any cause for this wreck. I'm expressing doubts and asking questions about your sun kink concept.
7j43k Euclid 7j43k And what did Russ say when asked why this didn't happen several weeks earlier, when the temperature was 12 degrees higher? And how did Russ know it was heat caused instead of a failure in track/roadbed installation? Ed However you seem to be positively asserting that a sun kink was not the cause. How can you be so sure? I'm guessing nobody asked Russ those questions. I'm not positively asserting any cause for this wreck. I'm expressing doubts and asking questions about your sun kink concept. Ed
I agree that you are not asserting a cause for the wreck. But what I said was that you are positively asserting that a sun kink was not the cause. And you are indeed doing that. Your statements indicate that. You have ruled out sun kink as the cause because there were no sun kinks when the temperature was higher than at the time of the Montana wreck. So you conclude that the temperature was not high engough to cause a sun kink in relation to the Montana wreck.
Euclid I agree that you are not asserting a cause for the wreck. But what I said was that you are positively asserting that a sun kink was not the cause. And you are indeed doing that. Your statements indicate that.
I agree that you are not asserting a cause for the wreck. But what I said was that you are positively asserting that a sun kink was not the cause. And you are indeed doing that. Your statements indicate that.
And you can show that by quoting me, of course. Please do.
You have ruled out sun kink as the cause because there were no sun kinks when the temperature was higher than at the time of the Montana wreck.
No. I have asked why it didn't happen at the higher temperature. Why do you think asking a question would rule something out.
So you conclude that the temperature was not high engough to cause a sun kink in relation to the Montana wreck.
Nope. But I do have doubts.
You seem to confuse having doubt and asking questions with negative certainty.
To be CLEAR:
I DO NOT ASSERT THAT THE CAUSE OF THIS WRECK WAS NOT A SUN KINK.
I believe the most likely cause was defective maintenance for the track/roadbed. The sun/heat MAY have exacerbated it, but I think it did not CAUSE the problem. Put another way, if the maintenance was done properly, I think there would not have been a derailment.
Note the words "I believe..." and "...most likely...". Clearly, that leaves room for others to believe differently. As you do.
Euclidif track is misaligned before the locomotive reaches it, it may make it across safely because it is heavier than the trailing cars and thus it can hold the track better.
Not criticizing you for passing this along, but I don't know if I buy this theory. Common sense would tell me that a heavy locomotive, in a curve, would apply more outward force than a lighter piece of rolling stock would, therefore making it more likely that the engine(s) would force the outer rail outward and splay the track.
Lithonia Operator Euclid if track is misaligned before the locomotive reaches it, it may make it across safely because it is heavier than the trailing cars and thus it can hold the track better. Not criticizing you for passing this along, but I don't know if I buy this theory. Common sense would tell me that a heavy locomotive, in a curve, would apply more outward force than a lighter piece of rolling stock would, therefore making it more likely that the engine(s) would force the outer rail outward and splay the track.
Euclid if track is misaligned before the locomotive reaches it, it may make it across safely because it is heavier than the trailing cars and thus it can hold the track better.
LINKED MEDIA QUOTE FROM PRIOR POST:
“Russ Quimby, a former rail-accident investigator for the NTSB, said heat is the most likely explanation. He is convinced because the locomotives in front did not derail, but eight lighter coach cars behind them did.
“This has all the earmarks of a track buckle also,” Quimby said. “Sometimes a locomotive, which is heavier, will make it through” a buckled track, “but the cars following won’t. You saw that in this accident,” he said.”
I agree with your point. Mr. Quimby makes the point to explain why locomotives tend to not derail in sun kinks, but the following rolling stock does derail. But there are several conditions that bear on the outcome if encountering sun kinks, including conditions that would result in the heavier locomotive having a greater tendency to derail in misaligned track than would the lighter rolling stock. The follow descibes factors affecting a variety outcomes with sun kinks:
On either curved or straight track, sun kinks become latent for some period of time before they manifest by beginning to misalign the track. This is because the rail expansion can be absorbed by directly compressing the rail for a period of time, but it eventually reaches the point where the rail will buckle rather than accept further compression.
So a train can encounter a sun kink that is visible as rail misalignment; or invisible as simply rail under excess compression. Either way, the train will accelerate the process of developing misalignment. If the sun kink is latent or invisible, the track is perfect as the locomotive encounters it, but it will start to misalign as the locomotive passes into the invisible state of sun kink.
The reason is that the train weight will work the track structure as the trucks press the track down and then allow it to slightly rebound until the next truck passes the same spot. This undulating action of the track will cause it to lose its grip on its anchoring in the rail, ties, spikes, tie plates, rail anchors, and ballast. This “loss of grip” will suddenly allow the rail to dissipate its built up compression by buckling.
Once the locomotive passes the start of the sun kink zone and initiates the rail buckling, the buckling progresses in the zone behind the locomotive even though the zone may be several hundred feet long extending ahead of the locomotive.
But since the sun kink has not yet reached the point of buckling on its own, it will not buckle ahead of the locomotive. It will only buckle behind it. And the buckling will grow worse as each successive car passes each point trailing the locomotive. So the locomotive is not entering a range of rail buckling and continuously worsens under the locomotive. The locomotive is always entering a range of perfect track that may only slightly degrade as the locomotive traverses a given point; and will continue to degrade as each car of the train passes over that given point.
I believe that this is the fundamental explanation of why the locomotive often makes it over a sun kink that later starts to derail the following cars in the train.
But this explanation is only for a train encountering a sun kink that is in the latent phase. If the sun kink is in the manifested phase, Mr. Quimby’s explanation may be applicable. In this circumstance, the sun kink has already buckled the rails on its own, and may have severely misaligned them.
However, I think this explanation could cut both ways. In a manifested sun kink, track will have two potential defects:
Excess curvature features.
Loss of support.
The heavier weight of the locomotive may hold the track better with #1. But it may increase the chance of derailment with #2.
EuclidOn either curved or straight track, sun kinks become latent for some period of time before they manifest by beginning to misalign the track. This is because the rail expansion can be absorbed by directly compressing the rail for a period of time, but it eventually reaches the point where the rail will buckle rather than accept further compression.
Are you sure about this? As heat causes the rail to expand in length, it seems to me it quickly reaches a point where that causes it to kink.
charlie hebdo Euclid On either curved or straight track, sun kinks become latent for some period of time before they manifest by beginning to misalign the track. This is because the rail expansion can be absorbed by directly compressing the rail for a period of time, but it eventually reaches the point where the rail will buckle rather than accept further compression. Are you sure about this? As heat causes the rail to expand in length, it seems to me it quickly reaches a point where that causes it to kink.
Euclid On either curved or straight track, sun kinks become latent for some period of time before they manifest by beginning to misalign the track. This is because the rail expansion can be absorbed by directly compressing the rail for a period of time, but it eventually reaches the point where the rail will buckle rather than accept further compression.
It would seem that way if the thermal expansion was an irresistible force, but it is not. If the rail is sufficiently constrained, its linear expansion can be restrained during thermal expansion.
The rail steel is made with sufficient elasticity, to make a rail act like a coil spring when squeezed end to end, and then rebound when the squeeze is released. It can also be stretched end to end and elongate like a coil spring, and then rebound from the stretch when the force is removed.
So if you heat rail that is constrained end to end, the steel itself will compress like bread dough. So the heated and constrained rail will absorb the expansion within the steel itself.
If rail could not be restrained from liner expansion by its elasticity, then it would indeed almost immediately cause buckling when heated. But such buckling would be very slow to occur because expansion is slow. The first buckling would not be visible to the eye. But what we often see happen is that pent up expansion suddenly releases by buckling of the track to the extent of what must be several inches of increased rail length being absorbed by buckling.
I am no expert, but I know the RR's have adapted a practice of attaching Rail Anchors to control the expansion. These are clamped onto the rail and are adjacent to the cross ties. My interpretation is that this causes the rail to expand vertically and become 'fatter' within the confines of the area between the ties.
Before this goes on too much further, consider the force restraining 'buckling' in the vertical plane, restricted by rail weight and fastening integrity to tie weight; force restraining movement in the longitudinal direction (controlled as noted by rail anchors and fastening including Pandrol clips when present); and lateral motion (tie friction; ballast end shoulders, etc.)
diningcar I am no expert, but I know the RR's have adapted a practice of attaching Rail Anchors to control the expansion. These are clamped onto the rail and are adjacent to the cross ties. My interpretation is that this causes the rail to expand vertically and become 'fatter' within the confines of the area between the ties.
Yup.
Maybe not "vertically", but "axially".
Overmod Before this goes on too much further, consider the force restraining 'buckling' in the vertical plane, restricted by rail weight and fastening integrity to tie weight; force restraining movement in the longitudinal direction (controlled as noted by rail anchors and fastening including Pandrol clips when present); and lateral motion (tie friction; ballast end shoulders, etc.)
And lack thereof.
Restraining track and rail buckling in every direction is used to constrain linear expansion of rail. But even if rail absorbs the expansion internally, its linear expansion force grows higher as the expansion absorbed within the rail increases.
At some point there will be buckling if the constrained expansion continues to increase. And once buckling happens, the force needed to move the track decreases as the track moves.
Just to keep things straight, may I offer these definitions:
sun kink: a rail dislocation caused by solar radiation
heat kink: a rail dislocation caused by heat input to the rail from the surrounding environment (includes solar radiation)
buckled track (or track buckle): a rail dislocation caused by any means
I do not see these phrases as interchangeable.
7j43k Just to keep things straight, may I offer these definitions: sun kink: a rail dislocation caused by solar radiation heat kink: a rail dislocation caused by heat input to the rail from the surrounding environment (includes solar radiation) buckled track (or track buckle): a rail dislocation caused by any means I do not see these phrases as interchangeable. Ed
I regard heat kink and sun kink as interchangeable, alternatives. What do you call it if the sun heats the rail and then goes under a cloud when the rail buckles?
Buckling in engineering terms is more specific than just any structural failure. It means failure of a column or slender beam caused by axial compression.
In a sun kink or heat kink, I cannot think of any term besides “buckling” that better describes the kinking of a rail due to its linear expansion being constrained.
In a sun kink, the track structure besides the rails is not buckling at all. It is just being deformed by the buckling of the rails. Rails are dislocated by derailments without any actual buckling. Rails break under train loading. Rails also break due to contraction. Both are means of track failure that do not involve buckling.
I know they do heat patrols/inspections on the lines I run when the temperature gets above 80F (I believe). I don't think whether the sun is shining or not plays into that. Maybe I'm wrong? I never asked the MOW foreman that question.
Fred M CainFor me, I was kinda hopin’ that someone would’ve had something more factual to report by now. I was checking online news services and this whole incident is kind of getting crowded out of the news already.
I was hoping and noticing the same thing. I suspect that when the investigation's complete the mainline media will have moved on and forgotten all about it.
So, we'll have to expect a report in "Trains" or possibly one of the professionals here will have learned what happened and pass it on.
Not being a professional railroader myself I've refrained from commenting on possible causes.
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