BaltACDthe bones of the skull to an extent are indestructable in comparison to brain tissue.
I think you will find that the proximate cause of most of these concussions is due to quite a different mechanism (but one that proves your point perhaps even better). What often happens is that a hard shock to the skull results in shock waves that are focused and reflected by the curve of the bone to where they cause the soft-tissue damage. Subsequent damage from the closed skull is much more associated with various forms of tissue swelling or fluid release than with direct damage from inertial deceleration.
There can certainly be inertial effects of the brain tissue inside the skull in high-speed trauma, but you will notice that most instances of high impact will result in skull fracture (and nothing more than concussion or some minor hematoma formation underneath) before gross traumatic brain injury -- this is likely not just a sampling artifact of analysis. The cushioning systems in the brain's surrounding tissues are reasonably good at cradling it against the kind of shock encountered in evolutionary survivable incidents...
The whole point of my having raised the issue of belts and elastic harnesses in these crashes is not primarily for restraint -- it is for impact management in the only place it really matters in heavy freight crashes. Decelerating the people at a rate that preserves them alive, while using "CEM" as a means of redirecting external force away from crushing whatever 'refuge' or cab zone the deceleration occurs in. Remember that CEM does not necessarily mean 'attenuation'; in fact some of the lateral-deflecting anticlimber designs explicitly use 'management' to mean vector change away from high-g-deceleration impact.
I highly suspect we will find the two men killed in the Cayce collision did not die of traumatic crush or rollover injury -- they died of prompt deceleration at high g. Even being in a padded refuge space, or dropping below even a capable long-travel controlled-crush zone, may not help in these situations. Certainly no amount of European-style nose or push-back coupler action would have helped much with this; it would only have staved off the lethal acceleration change as long as the crumpling was taking place. Proper "CEM" as the analogue of interior padding and active elements such as air bags is the way you save lives in such incidents. And, as in automotive practice, one effective way to get the controlled deceleration over full distance is to use pretensioned inertia-reel control in harness or belts, not to hold victims pinned for the squish, but to just stop them from hitting something harder than to bruise.
EuclidOne way I think it could happen is if you did actually have indestructible cabs in a head-on collision, and the locomotives totally disintegrated except for their cabs, and then the two cabs hit head-on.
When reduced to a smaller scale - the 'indestructability' of the skull is the cause of concussions in sports - the bones of the skull to an extent are indestructable in comparison to brain tissue. Severe impact and brain tissue crushes itself against the skull and there you have concussions and brain injury.
Never too old to have a happy childhood!
In you described case you would have a crumple zone.
In the 1995 the FRA researched a head-on collission of two trains, one with 5 locomotives and 92 cars, the other with 2 locomotives and 15 cars with combined velocity of 30 mph.
None of the locomotives were compliant with the AAR S-580 requirement of the times. The used this scenario as a baseline calculating impact on locomotive and occupants. Than the calculated the same scenario but with S-580 compliant locomotives, and ones with more rigid posts than required by S-580.
The baseline had the largest damage to the locomotive but the least impact on the occupants if the cab had stayed intact. But the cab got partly crushed.
The more rigid the post in the hood got, the higher the impact on the occupants:https://rosap.ntl.bts.gov/view/dot/8456/dot_8456_DS1.pdf?
The researched some additional measures like interlocking but not deformable anticlimbers. In that case the peak deceleration was 15g in the other cases 11g.
Just as a comparison the European standards allow a mean deceleration of 5g and a peak of 7.5g.
Another interesting read: onlinepubs.trb.org/onlinepubs/trnews/trnews286CrashTest.pdfRegards, Volker
There was an earlier thread about seat belts and restraints for train crews. They would only lead to more deaths. I would and so would many who replied to the thread that hitting the floor gives you a much better chance of suvival than selt belts or retrainsrs
One way I think it could happen is if you did actually have indestructible cabs in a head-on collision, and the locomotives totally disintegrated except for their cabs, and then the two cabs hit head-on.
EuclidHas getting killed by too much decleration ever happened with freight trains?
Considering the damage that occurs during a collision between a train and an immovable object (or one of significant mass moving in the opposite direction), and that I don't believe there are any restraints in locomotives, I would say that the possibility of being killed (or significantly injured) by the sudden stop (or rapid decelleration) does exist.
It would be just one of many factors, as you note, and will depend heavily on the rate of decelleration. If we're talking a direct head-on, both locomotives will go from whatever speed to zero in a split second. If the crew sees it coming and heads for the floor they'll stand a better chance for the decelleration portion (ie, no face plant in the windshield). The structural failure of the cab and the rest of the locomotive is another story.
Given the level of destruction that will occur, I suspect it would be hard to specifically say that the secondary collision of the crewmember into the windshield was a significant factor in their injuries
The relative infrequency with which such collisions occur would preclude anything like seatbelts or airbags. Even padding on consoles, etc, would be useless in a major collision.
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...
VOLKER LANDWEHR BaltACD The tonnages of todays Class 1 freight trains posess more force in their momentum than virtually ANYTHING designed and built by man can withstand at the point of impact. CEM on freight locomotives will not solve all problems but CEM can reduce the aftermath. Under some circumstances the FRA- Crashworthiness compliant freight locomotive might still have a quite intact crew cab but the crew didn't survive because of too high deceleration and impact. CEM can reduce both. Regards, Volker
BaltACD The tonnages of todays Class 1 freight trains posess more force in their momentum than virtually ANYTHING designed and built by man can withstand at the point of impact.
CEM on freight locomotives will not solve all problems but CEM can reduce the aftermath. Under some circumstances the FRA- Crashworthiness compliant freight locomotive might still have a quite intact crew cab but the crew didn't survive because of too high deceleration and impact. CEM can reduce both.
Regards, Volker
Has getting killed by too much decleration ever happened with freight trains? I suppose it could if the tonnage is low enough, but generally, it seems that nothing can decelerate fast enough to injure the cab occupants because the tonnage just shoves everything ahead until it jackknifes, overrides, or disintegrates in a way that displaces it from the line of force of all the trailing tonnage. It seems to me that what kills crews is the cab disintegrating in this process. What is needed is an indestructible cab.
There is so much force that a sufficient crumple zone would take up the the entire locomotive several times over.
BaltACDThe tonnages of todays Class 1 freight trains posess more force in their momentum than virtually ANYTHING designed and built by man can withstand at the point of impact.
I don't know what you would do but I would never again use a car without CEM/crumple zone.Regards, Volker
A typical US passenger train will be < 1,000 tons, whereas a freight train can easily be 10,000 to 15,000, possibly 20,000 tons.
The passenger train might be going faster - and the energy varies with the square of the speed, whereas momentum is linear with the speed - but it's got better set-up with designed Crash-Energy Management (CEM) zones, which the freight trains don't have. All they have is the rigid anti-climbers and collision posts in the nose, or the engine &etc. equipment in the long hood. And I understand that the supposed energy-absorbing feature of the early F- and GP- series EMD locomotives bending (not crumpling) just behind the cab was coincidental and happenstance, not designed-in (wouldn't be worth much in a high-energy collision anyway).
- PDN.
VOLKER LANDWEHR BaltACD And comparing the tests in the video to the actual NS collision is also a illusion. First of all we were talking about the overridung problem and nothing more. Push-back couplers and deformable anticlimbers can avoid it. BaltACD In the NS collision you are dealing with a probably 10K ton or more train that is stopped, most likely with air still applied and a 10K or more train moving at 30 or so MPH. Real world vs the tests are apples and oranges. The other question, could CEM have minimized the damage and saved the live of the crew? I don't know. As I said before there are accidents the best crashworthiness design can handle. When Europe developed its EN 15277 the commitee checked about 900 accident reports. The EN crash scenarios would have covered about 80%. The FRA has similar scenarios in their Alternative crashwortiness design. If the NS collisions falls into the not to handle category I don't know. You can design a CEM system to run against an unmovable wall. Up to which energy (mass and speed) depends on the availabe space and material. The Volpe National Transportation Systems Center of the US DoT and others have done a lot research on CEM crashworthiness design that led to the FRA Alternative Crashworthiness Design and passenger car CEM requirements. One of the results was that you are better of in CEM passenger cars than in conventional American equipment: https://www.fra.dot.gov/Elib/Document/2125 Hopefully the number of these kinds of accidents will be reduced by PTC.Regards, Volker
BaltACD And comparing the tests in the video to the actual NS collision is also a illusion.
First of all we were talking about the overridung problem and nothing more. Push-back couplers and deformable anticlimbers can avoid it.
BaltACD In the NS collision you are dealing with a probably 10K ton or more train that is stopped, most likely with air still applied and a 10K or more train moving at 30 or so MPH. Real world vs the tests are apples and oranges.
The other question, could CEM have minimized the damage and saved the live of the crew? I don't know.
As I said before there are accidents the best crashworthiness design can handle.
When Europe developed its EN 15277 the commitee checked about 900 accident reports. The EN crash scenarios would have covered about 80%. The FRA has similar scenarios in their Alternative crashwortiness design.
If the NS collisions falls into the not to handle category I don't know.
You can design a CEM system to run against an unmovable wall. Up to which energy (mass and speed) depends on the availabe space and material.
The Volpe National Transportation Systems Center of the US DoT and others have done a lot research on CEM crashworthiness design that led to the FRA Alternative Crashworthiness Design and passenger car CEM requirements.
One of the results was that you are better of in CEM passenger cars than in conventional American equipment: https://www.fra.dot.gov/Elib/Document/2125
Hopefully the number of these kinds of accidents will be reduced by PTC.Regards, Volker
The tonnages of todays Class 1 freight trains posess more force in their momentum than virtually ANYTHING designed and built by man can withstand at the point of impact.
BaltACDAnd comparing the tests in the video to the actual NS collision is also a illusion.
BaltACDIn the NS collision you are dealing with a probably 10K ton or more train that is stopped, most likely with air still applied and a 10K or more train moving at 30 or so MPH. Real world vs the tests are apples and oranges.
BaltACD Real world vs the tests are apples and oranges.
Real world vs the tests are apples and oranges.
More like apples and battleships.
It seems like a left or right diversion would be better in this case. Aside from fouling another line, which usually happens anyway with the other cars.
edblysardWhat is the average weight in imperial tons of a European freight locomotive?
four-axle locomotives around 100 tons, six-axle units about 140 tons.
The question was the failure of the convenional FRA-compliant anticlimber. There are a lot of accident reports and tests showing that this kind of anticlimber often doesn't work as intended.
The push-back coupler and the deformable anticlimber allow the vehicles to interlock and prevent overriding, while the FRA-anticlimber inhere the danger that a vehicle is deflected upward.
And so far this is independent of locomotive weight. In this case the push-back deformable anticlimber combination is not used as CEM element but an overriding prevention.Regards, Volker
And comparing the tests in the video to the actual NS collision is also a illusion.
1 car vs 1 car and even 5 cars vs 5 cars. One question not illuminated in the video - was the standing car(s) secured by hand brake?
In the NS collision you are dealing with a probably 10K ton or more train that is stopped, most likely with air still applied and a 10K or more train moving at 30 or so MPH. Real world vs the tests are apples and oranges.
23 17 46 11
Thank you for posting. The video is much easier understood than my links.
BTW what you see in the video are CEM constructions according to European standards.Regards, Volker
blue streak 1 Anti climbers do not alway work do they ?
Anti climbers do not alway work do they ?
https://www.youtube.com/watch?v=OlqZDkOTUDQ
I think it is a known fakt that anticlimbers don't always work as intended. The 2011 Red Oak accident is an example.
Research by the Volpe National Transportation Systems Center of the US DoT have shown that push-back couplers and deformable anticlimbers show better results.
That is on reason that passenger locomotives like EMD F125, Siemens Sprinter and Charger are equipped with push-back couplers and Crash Energy Management Anticlimbers. Animation conventional versus CEM couplers:https://www.youtube.com/watch?v=JPXtOUWPWWg
And a report: https://rosap.ntl.bts.gov/view/dot/12370/dot_12370_DS1.pdf?Regards, Volker
Edit: Replaced the second identical link with the right one
Crew saw the stop signal when they woke up. Another fatigue caused accident.
samfp1943Call me a little paranoid, but it seems to suggest, that on the basis of the time [local: 11PM], and no indications of limitions to his vision; there may be an underlaying undiagnosed medical condition in the 'overrunning engineer' ? Might even be a problem with distance of the signal's visibility; due to, maybe, some local condition?
I would tend to wonder if the previous incident occurred under similar conditions - as you say, it might be something this particular individual has a problem with.
Or, if there is something in the physical characteristics that causes a problem. I wouldn't think it's a signal issue - the train would have gotten an approach aspect of one sort or another at an earlier signal, and assuming familiarity with the line, the engineer would have known where to make the stop.
So I wonder if he miscalculated speed/weight/stopping distance. I've never been faced with a pending collision, but there have been times when I wondered if that application I put on was ever going to take...
jeffhergert BaltACD Semper Vaporo That does not look like a "head on" collision... unless the NS unit was being run Long Hood forward. That looks like the train with the BNSF engine ran into the rear of the NS train. My understanding from another forum was the BNSF was the leader of the NB. The frame was the leader of the SB, the 2nd unit of the SB is the one in the air. How the SB crew survived, the Almighty only knows. I wasn't there so everything I have said could be wrong. From another site. Train on double ran his stop. Train on single (running on approach diverging) hit the stopped train. Perfect storm. The train on single was to close when the train on double announced they were by it. Word is they were running out the back door. Emergency at 38mph & hit at 32. "...Also on this site, they are talking that the engineer who overran the stop signal did so once before and served time off. That this location is the same place where his first violation happened..." Jeff Call me a little paranoid, but it seems to suggest, that on the basis of the time [local: 11PM], and no indications of limitions to his vision; there may be an underlaying undiagnosed medical condition in the 'overrunning engineer' ? Might even be a problem with distance of the signal's visibility; due to, maybe, some local condition?
BaltACD Semper Vaporo That does not look like a "head on" collision... unless the NS unit was being run Long Hood forward. That looks like the train with the BNSF engine ran into the rear of the NS train. My understanding from another forum was the BNSF was the leader of the NB. The frame was the leader of the SB, the 2nd unit of the SB is the one in the air. How the SB crew survived, the Almighty only knows. I wasn't there so everything I have said could be wrong.
Semper Vaporo That does not look like a "head on" collision... unless the NS unit was being run Long Hood forward. That looks like the train with the BNSF engine ran into the rear of the NS train.
My understanding from another forum was the BNSF was the leader of the NB. The frame was the leader of the SB, the 2nd unit of the SB is the one in the air. How the SB crew survived, the Almighty only knows.
I wasn't there so everything I have said could be wrong.
From another site.
Train on double ran his stop. Train on single (running on approach diverging) hit the stopped train. Perfect storm. The train on single was to close when the train on double announced they were by it. Word is they were running out the back door. Emergency at 38mph & hit at 32.
"...Also on this site, they are talking that the engineer who overran the stop signal did so once before and served time off. That this location is the same place where his first violation happened..."
Jeff
Call me a little paranoid, but it seems to suggest, that on the basis of the time [local: 11PM], and no indications of limitions to his vision; there may be an underlaying undiagnosed medical condition in the 'overrunning engineer' ? Might even be a problem with distance of the signal's visibility; due to, maybe, some local condition?
Also on this site, they are talking that the engineer who overran the stop signal did so once before and served time off. That this location is the same place where his first violation happened.
Semper VaporoThat does not look like a "head on" collision... unless the NS unit was being run Long Hood forward. That looks like the train with the BNSF engine ran into the rear of the NS train.
Yeee-ouch! Someone get that loco a new Cannon Shell.
That does not look like a "head on" collision... unless the NS unit was being run Long Hood forward. That looks like the train with the BNSF engine ran into the rear of the NS train.
Semper Vaporo
Pkgs.
BaltACD Info I have recieved is that the SB had trouble controlling his train in response to the STOP signal - and had communicated with the NB who stopped just short of the Control Point. SB slid through the STOP Signal.
Info I have recieved is that the SB had trouble controlling his train in response to the STOP signal - and had communicated with the NB who stopped just short of the Control Point. SB slid through the STOP Signal.
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