RME Erik -- sorry, I have no idea why I thought that was you. I have edited the post accordingly. (I did think it was a bit strange you'd say manual monitoring would be necessary...)
Erik -- sorry, I have no idea why I thought that was you. I have edited the post accordingly. (I did think it was a bit strange you'd say manual monitoring would be necessary...)
Absolutely no problem, I thought it was rather amusing.
I also aree on issues with the cameras, have enough fun keeping the lens of the back-up camera on our newest car clean and would hate to think how infrequently the lenses on a truck would be cleaned.
There has been a lot of interest in wireless sensors for industrial use driven by a typical cost of $20/ft in the early aughties for factory floor wiring (reported by Wayne Mangess of ORNL). On of the applications was monitoring motor bearings, which would be a bit similar to the truck problem. Energy harvesting was being developed in order for the sensor to be truly wireless.
RMEThere won't be any magic here. I doubt that the reaction to a radio UDE tone would ever be for every engineer hearing it, near or distant, to instantly plug their train; it would be handled through the equivalent of a RTC or dispatcher, with human reaction times and communications channels, and instructions relayed to affected trains. Conversely, a dispatcher couldn't see the blowing snow, which was a major factor here, so almost certainly his order to a loaded oil train passing another train would be to brake safely in some service position.
I agree that the reaction to a UDE alert would not be for every engineer hearing it to make an emergency application. In most cases, even the most affected train would not need to make an emergency application. But I don’t see how the alert could be processed through communications to the dispatcher and instructions back to the affected trains. It is an emergency that can call for instant response by those affected. As the Road Foreman of Engines on the grain train put it:
“You would expect that a train approaching you [i.e. the oil train which was the subject of the warning] to immediately reduce their speed, protect themselves, maybe even stop, as conditions might require. I don't know that there's anything absolutely written in stone other than you'll get your train speed down, control, and you'll -- if I was on the train, we'd proceed looking out for hazards in front of us.”
Of course, in this case, if the engineer of the oil train never heard the announcement, that explains why he did not react to it. But had he heard the announcement, I think an emergency application would have been the safest course. “Immediately reducing speed and protecting yourself” could not be accomplished by a service application in this case.
Here is a mechanical-pneumatic derailment detector that dumps the air when it senses the physical forces that a derailment imposes on a railcar:
http://www.knorr-bremse.com/media/documents/railvehicles/en/en_neu_2010/Brochure_EDT_101_derailment_detection_system.pdf
Here is the derailment detector used in Spain. What provides derailment detection with this device is the mechanical disruption of the proximity of the truck and carbody relationship. This is clearly shown in detail about 2/3 through the video or so.
When a wheel leaves the rail, it abruptly drops down the height of the rail, and lands on the ties. Since the carbody is riding on the other three axles, it remains relatively stable compared to the derailed wheelset. So there is an unusually large movement with the truck frame with the derailed wheelset compared to the carbody.
The derailment sensor physically feels for this excessive differentiation of position of the two bodies. If it detects excessive differentiation, it dumps the trainline air which makes an emergency application.
https://www.youtube.com/watch?v=VEzsEQHkQ-Y
Both of these concepts seem robust, simple, and reliable for use with conventional air brakes. Why make it any more complicated? With ECP brakes, the signal line could transmit derailment data if there were a need for that. Also with ECP brakes, the signal line could set the brakes simultaneously, and thus mitigate the issue of a detector initiating an emergency application directly from the point of derailment, at some mid-train location.
RME- Thanks for the explanation. Once you mentioned the yaw of the trucks, it clicked in my head and understood it.
Thanks to Chris / CopCarSS for my avatar.
erikemI've also heard enough over the years about industrial wireless sensors and various forms of energy harvesting to think that there are a fair number of non-video means of instrumenting a truck. Accelerometers and MEMS gyros can be quite cheap as long as you don't need INS accuracy.
Here the cell-phone craze has worked to significant advantage: very, very cheap accelerometer cores that 'double' as clinometers are available for a few cents apiece, with well-documentable accuracy and relatively easily implementable precision. Much of the other hardware needed for a good standalone, low-maintenance solution comes from similar sources.
I would suspect that the easiest way to harvest energy would be from vibration and a small low-cost capacitor could store enough energy to get a useful signal out.
That is right. Note however that there's more than enough vibration to charge even substantial batteries in a short time.
You could back up with solar power, as earlier indicated, as a backup to mechanical charging when the car sits for an extended period. There are similar objections to those used for optical derailment detection; hardening the panels in a typical railroad environment can be difficult; it is easy for thieves to divert the panels to other uses.
Note that there are a number of ways that active charging, for example via induction, could be implemented. This includes charging during the physical 'walk of the train' during inspections.
Murphy Siding If I understand your explanation correctly, the sensor would be tripped when a truck pitches too far to the left or right, presumably predicting that it had gone too far out of the norm and a derailment was imminent?
I don't have links to the Spanish system or its patents handy, but it was discussed in at least one of the Creeping Lovecraftian Horror threads. It is not the pitch of the truck that is detected, it is the yaw about the center pin, and in the Spanish system the "detection" is nothing more than an emergency trip when the truck yaws past the angle that represents the effect of the sharpest curve on the route.
A more sophisticated 'detection' would take account of the damped yaw rate as well as the absolute angle, since no intended curving would generate fast yaw, and any acceptable sideframe play or other cause of excessive uncontrolled bolster yaw would not have substantial magnitude.
Would the system then initiate an emergancy brake application on its own, or would it just alert the engineer of a problem?
The Spanish system is very simple, just a trip and a mechanical valve. A system that 'warned the engineer' would require all sorts of additional complication -- a separate tone in the radio, some means of identifying where in the train the incident occurred, there are many possibilities that I don't want to encourage a detailed discussion of -- and their discussion noted that if the truck has rotated to the angle it trips the valve, it's appropriate to stop the train in minimum time anyway. I would like to hear from buslist and others if this is indeed the 'best' appropriate strategy, given the expected propagation in the train.
How far would you think a truck would have to be off-kilter before the alarm went off? I've seen a train of empty rock gondolas on a bad track doing pretty spooky looking things. The cars appeared to tip left then right about 12" off vertical in quick succession, at about 10 mph. Would something like that tend to set off the alarm?
No. Only actual yaw sufficient to trip the valve would set the 'alarm', and it would do it by triggering a big-hole reduction propagating from the valve location down the trainline in both directions.
I assume you have seen the Government video on 'how to derail a train'. Three-piece trucks are extremely flexible in pitch, and can tolerate amazing amounts of 'twist' well past the point that the blocks above the roller-bearing housings are tipped in the sideframes without derailing. There is no particular reason to use sideframe pitch alone as a derailment indicator (unless so paranoid about safety that you'd plug it at every tree).
Likewise, harmonic rock should not be used to trigger a mechanical valve, although it might be highly useful to warn an engineer when movement has built up to the degree you indicate -- I'd think 5 degrees of repeated magnitude would be alarming, let alone 12, but I'd defer to professional rails on just how much rock constitutes a need for warning.
Yes, I'd put some kind of small whistle on any mechanical 'derailment detector' valve to make it easy to find the 'anomalous car' at zero-dark and wet-thirty. Perhaps cheap battery-powered lights near the sill, too.
BaltACD zugmann dehusman Where do you get a bright patch at night or in a tunnel or in water? Or protect said camera from the water spray, dust, mud, and other gunk that gets thrown up from the wheels? In curve territory there are a lot of 'greasers' - grease and optics go well together. NOT!
zugmann dehusman Where do you get a bright patch at night or in a tunnel or in water? Or protect said camera from the water spray, dust, mud, and other gunk that gets thrown up from the wheels?
dehusman Where do you get a bright patch at night or in a tunnel or in water?
Where do you get a bright patch at night or in a tunnel or in water?
Or protect said camera from the water spray, dust, mud, and other gunk that gets thrown up from the wheels?
In curve territory there are a lot of 'greasers' - grease and optics go well together. NOT!
What part of 'that's why I discarded the optical approach early' is still unclear to readers of this thread?
(The 'structured light source' of course would be designed to work under both strong ambient light and in the dark; you'd use a simple IR illumination (like the approach in a "0 lux night shot" video camera) otherwise. For nitpickers: obviously using IR only at night and visible spectra in daytime...)
Murphy SidingI believe I'd prefer a root canal to that scenario.
AMEN!
Norm
RME tree68 All of the data (either downloaded from the car or from a camera that's been swapped out) will require manhours to analyze. Erik, you know better than that -- this application is one of the poster children for expert-system artificial intelligence and machine vision.
tree68 All of the data (either downloaded from the car or from a camera that's been swapped out) will require manhours to analyze.
Erik, you know better than that -- this application is one of the poster children for expert-system artificial intelligence and machine vision.
I think Tree68's name is Larry....
I would certainly know betterthan that, having heard about GE's work on machine vision some 10 years ago.
I've also heard enough over the years about industrial wireless sensors and various forms of energy harvesting to think that there are a fair number of non-video means of instrumenting a truck. Accelerometers and MEMs gyros can be quite cheap as long as you don't need INS accuracy. I would suspect that the easiest way to harvest energy would be from vibration and a small low cost capacitor could store enough energy to get a useful signal out.
- Erik
RME Murphy Siding RME- How would a derailment detector work? At the risk of making you plow back through other Buclidean threads, we discussed some of the alternative technologies at length -- great and exhaustive length -- in some of the posts on differential braking and the like............
Murphy Siding RME- How would a derailment detector work?
At the risk of making you plow back through other Buclidean threads, we discussed some of the alternative technologies at length -- great and exhaustive length -- in some of the posts on differential braking and the like............
Never too old to have a happy childhood!
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
Dave H. Painted side goes up. My website : wnbranch.com
tree68All of the data (either downloaded from the car or from a camera that's been swapped out) will require manhours to analyze.
This application is one of the poster children for expert-system artificial intelligence and machine vision.
And the cameras are fixed and potted to the sideframes -- not coming off unless known defective. Not necessarily bigger, with local processing and power storage, than half an M&M.
What provides the 'derailment detection' here is the loss of running relationship between the bright patch from the wheeltread and the bright patch from the railhead. Naturally you have to discriminate what happens when the wheel runs over frogs or hits leaves that have been hardened into the usual dark plastic-like mass -- this is a major reason why fast-acting machine-vision systems at low enough cost haven't been deployed yet (they are just now coming into use on high-speed track-inspection systems)
There's a surprisingly large amount of pre-processing that can be done very fast in modern logic, to recognize common causes of "LOS" and deal with it appropriately. At least some of this recognizes that the correct response to what looks like a derailment is NOT to promptly plug the train in all cases; while the response for, say, a differential-braking setup may be complex, the command signals and subsequent monitoring (and fault workaround, etc.) are comparatively easy to define and implement. The fun will come in when different vendors try implementing proprietary technology that supposedly works to common open standards.
BaltACDI am sure the Car Department would love replacing and documenting 800 devices every 1000 mile inspection.
Power would be the issue - and a solar solution (more $$$) would probably handle it most of the time.
I suppose it would be possible to passively download each car, at least an "error" report. Depending on how much data there was to pass, it might be possible at a yard. Our local utility reads meters at pretty much highway speeds, unless the meter is a distance off the road.
All of the data (either downloaded from the car or from a camera that's been swapped out) will require manhours to analyze.
But that's still after-the-fact. A derailment detector has to work in real-time. Perhaps sending out a burst to the EOT receiver with car number and some form of code would help - but only in a dragging incident. If the car digs in immediately, the information has virtually no value, except as an investigation tool.
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...
They'd likely be permanently bonded to the sideframes and run continuously (an advantage of extremely-low-current electronics and 'harvested power' sources) so all the car department would do would be run a canned test-and-exercise routine on the devices. Any problem or issue, like damaged or obscured objective lenses, would have been apparent from the datastream long before the date and time of the car inspection, and 'time and parts' allocated for any such work reasonably far in advance.
The setup I designed had full specifications for jigs that were applied to any sideframe to simplify removal and deployment bonding of the devices in correct alignment, etc. No more specialized training needed than for making field splices in communications glass fiber with one of the automatic kits (my daughter when four could both do the splice and test the result without particular difficulty...)
What I was far more concerned with was the analogue for wheels of the result Strasburg had when they first started testing boilers with ultrasonic NDT -- they didn't call it the 'death ray' for nothing! It is possible that the system will detect many more early defects than expected, and there's no guarantee that a 'factor of safety' erring on the side of false positives might be overcompensatory for some types of damage (such as small flatting that has started producing shelling or other progressive defect) that are currently deferred by 1000-mile inspections.
RME DS4-4-1000 Oddly enough, if the '8 video cameras' use current cell-phone camera cores, and the 'PC' is a modified low-power PLC-like device running machine-vision software, that's a cheap and easy way to monitor the relative position of the wheel tread and rail positions (not as a video image, but a comparison of reflected bright spots with a structured light source). Note where the cameras and structured-light sources on a typical three-piece truck frame would go, and how power and data flows would be provided there. In my opinion, this approach has some problems, particularly including grime buildup, which makes it relatively unfavorable as a critical derailment detector. It would, however, serve nicely to detect other things, like potential flange breakage or tread scarring, should there be perceived value in being able to look for such things in realtime or for automated analysis.
DS4-4-1000
Oddly enough, if the '8 video cameras' use current cell-phone camera cores, and the 'PC' is a modified low-power PLC-like device running machine-vision software, that's a cheap and easy way to monitor the relative position of the wheel tread and rail positions (not as a video image, but a comparison of reflected bright spots with a structured light source). Note where the cameras and structured-light sources on a typical three-piece truck frame would go, and how power and data flows would be provided there.
In my opinion, this approach has some problems, particularly including grime buildup, which makes it relatively unfavorable as a critical derailment detector. It would, however, serve nicely to detect other things, like potential flange breakage or tread scarring, should there be perceived value in being able to look for such things in realtime or for automated analysis.
I am sure the Car Department would love replacing and documenting 800 devices every 1000 mile inspection.
DS4-4-1000Do we have to retrofit each and every railcar with 8 video cameras and a PC to monitor the position of the wheels?
On-car derailment detectors will occur when either they become economically desireable (probably never) or they are mandated (which would look a lot like the implementation of PTC).
Like the infamous Ford Pinto - as long as it is cheaper to pay for the occasional derailment, there's no real reason to install such detectors on every single car.
There are derailments every day. Most occur at low speeds. Incidents such as this one are very, very rare.
DS4-4-1000 Euclid Murphy Siding RME- How would a derailment detector work? It would have detected the initial derailment of the grain train, and set the brakes at that point. I'm still with Murphy Siding. How would a derailment detector work? Do we have to retrofit each and every railcar with 8 video cameras and a PC to monitor the position of the wheels? Not gonna happen.
Euclid Murphy Siding RME- How would a derailment detector work? It would have detected the initial derailment of the grain train, and set the brakes at that point.
I'm still with Murphy Siding. How would a derailment detector work? Do we have to retrofit each and every railcar with 8 video cameras and a PC to monitor the position of the wheels? Not gonna happen.
Just to clarify, I am referring to derailment detectors or sensors that are mounted on the freight cars, as opposed to a lineside device.
The key point is that while a derailed-dragging condition indicates the start of an emergency; without a derailment detector, there will be no application of brakes unless the crew sees the derailed car dragging and makes the brake application. Once a pileup begins, the air hoses part and the train automatically goes into emergency. But the nature of a derailed-dragging phase is that no air hoses part, and so no brake application is automatically made. So the derailment detector senses the derailment involved in the dragging, and makes a brake application.
There are various technologies invovled with derailment detectors, and they do monitor evey wheelset. Some are purely mechanical-pneumatic. Of course the industry will resist the use of derailment detectors. But they are being adoped in other countries such as India.
Murphy SidingRME- How would a derailment detector work?
At the risk of making you plow back through other Buclidean threads, we discussed some of the alternative technologies at length -- great and exhaustive length -- in some of the posts on differential braking and the like.
The current Spanish device which triggers an emergency application when the truck yaws beyond a certain point could easily be equipped with contacts or a simple pull-out arrangement that would trigger the rail equivalent of an ELT. This in fact could probably be arranged to 'squawk' information about the particular car involved, or even some event-recorder-like information starting with the last few seconds before the triggering occurred, and then streaming information like the attitude or momentum or vibration of the car (easily deduced from the angle and position of the attached transponder via cheap accelerometer cores)
Another approach involves instrumenting parts of the trucks themselves to detect aspects of 'derailed-car behavior' -- I'm currently under NDA on this technology but it is becoming highly refined and relatively cost-effective.
I think extending WILD coverage to give shorter intervals between detector stations is highly valuable, and until there is fairly widespread installation of on-car detectors (not likely unless and until mandated - and incomplete until substantial buildout is achieved) it's the default standard. However, that approach can't ensure that every derailment would be caught before an incident or accident ensues. We could speculate on whether a WILD would be installed near the location the signal maintainer was 'working' (since the communications, cabinets, etc. would be easily provided for it there) BUT it would seem that an alarm from a device in that location would have given very short warning in this particular case. I think installing more WILDs is certainly worth doing, and keeping after individual car detectors are in place.
If we assume data-network integrity of the kind required for PTC, the provision of effective onboard derailment detection and warning via a modulated tone should be relatively easy to provide (especially if Meteorcomm has done their job right with the implementation of SBRs).
[EDIT - note that I did not mention dragging-equipment detectors. Those are certainly useful, but no one sane would consider them as standing in for critical derailment detectors.]
EuclidMurphy Siding RME- How would a derailment detector work? It would have detected the initial derailment of the grain train, and set the brakes at that point.
RME- How would a derailment detector work?
It would have detected the initial derailment of the grain train, and set the brakes at that point. Evidence suggests that this derailment began a derailed-dragging phase that persisted for some considerable distance before the cars began piling up and ultimately fouled the other track.
There may have been time during the derailed-dragging phase to brake the train sufficiently to prevent a pileup; if a derailment detector began braking as soon as the derailment happened. If there was no fouling during the derailed-dragging phase, and if the train did not ultimately pile up and foul, the oil train would have passed without colliding with anything.
Current derailment detectors make an emergency application the instant that the first wheelset leaves the rail. If the train immediately begins to pile up at that point, the derailment detector offers little benefit. But for derailments that begin with a derailed-dragging phase, a derailment detector can prevent a pileup.
EuclidThe first announcement comes from the grain train. In his interview, the Road Foreman of Engines talks about telling the conductor to make this announcement, which is broadcast as “Train in emergency.” Next comes another announcement stating, “Emergency, emergency, emergency,” which is heard prior to the derailment of the oil train. Who made that second announcement?
This has gone on long enough.
The "Emergency, emergency, emergency" is clearly from the same person on the grain train who made the 'train in emergency' call; he realizes he has not followed the "correct" form of the call and proceeds to follow the rule in a somewhat desultory tone.
We should remember that according to the testimony, the grain train was already braking to let someone off, which was given as a reason why the occurrence of the UDE was recognized late. I did not see the NTSB ask the specific question about whether a perhaps unexpectedly 'normal' deceleration in snow/ice conditions shoulda-woulda-coulda set off alarm bells for the crew; perhaps the matter will come up later as we all know 20/20 hindsight is so accurate retroactively in pending emergencies. Please let's not belabor it here.
The only remaining 'what if' in this situation is, if there had been a Canadian-style tone alert on detection of the grain train's actual UDE, (1) how long would it have taken for the alert to be 'processed' to the point the key train applied its own brakes; (2) what type of braking -- full-service or emergency -- would rules have called for in such conditions; and (3) how long would subsequent physics ... use the curves in the one-pipe vs. ECP comparison if you don't want to argue about math ... say it would take to stop the train, and how fast would it have been moving at the time it encountered the hopper.
There won't be any magic here. I doubt that the reaction to a radio UDE tone would ever be for every engineer hearing it, near or distant, to instantly plug their train; it would be handled through the equivalent of a RTC or dispatcher, with human reaction times and communications channels, and instructions relayed to affected trains. Conversely, a dispatcher couldn't see the blowing snow, which was a major factor here, so almost certainly his order to a loaded oil train passing another train would be to brake safely in some service position.
A derailment detector or other instrumentation would have provided some extra seconds of warning -- we can, and probably will, debate ad nauseam on exactly how many. Then we could rehash how the oil-train crew 'could' have responded to the earlier warning, but this would still involve first the notification procedure and then the reasoned response in context.
What is missing from all the spasms in this thread is what can practically be done, either by railroads or the FRA, to reduce either the likelihood or the magnitude of accidents like this in the future.
Here is a narrated version of the Casselton derailment video. I am not sure who is doing the narration. It may not be the NTSB. But, in any case, the narration adds helpful explanation for those who are watching for the first time.
http://www.valleynewslive.com/content/news/2013-Casselton-oil-train-explosion.html
However, this narrated version does raise a couple questions. The narrator says that each train made an emergency announcement. Accordingly, the video gives the audio of two different announcements from train crews, which indicate that a train has made an emergency application of brakes.
The first announcement comes from the grain train. In his interview, the Road Foreman of Engines talks about telling the conductor to make this announcement, which is broadcast as “Train in emergency.”
Next comes another announcement stating, “Emergency, emergency, emergency,” which is heard prior to the derailment of the oil train. Who made that second announcement?
According to the narrator, the oil train made its emergency announcement after the collision. That would have been when the engineer said “We are everywhere, we are on fire, we are a key train, etc.”
So who made the announcement, “Emergency, emergency, emergency” heard before the derailment?
BaltACD Euc - when you learn how to apply rules in the real world get back to us.
Euc - when you learn how to apply rules in the real world get back to us.
I'm sure you meant reality rather than rules.
Why bother?
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