Note that I was referring to the 2019 initial report; the 2021 report does not appear to add anything in most of the key observations there, and in fact seems to be ignoring several important ones.
Note that the 2021 report refers to electronic speaker-type devices that can 'replace' train horns, capable of the modulations that (as seem to be carried over from the 2019 report) conform to their types #9 and #10. I see little likelihood of these being any more 'popularly adopted' than the UP sirens were, let alone becoming adopted as an unfunded mandate. Much the same is likely true of a 'trespasser alert' or emergency signal provided in parallel with mandated air horns.
It would be comparatively easy to equip the 'two emergency bells' of a split Canadian horn with secondary drivers similar to those used on large horn-type speakers, which can be either (1) modulated at any emergency frequency spectrum mentioned as effective in the report, or (2) used to modulate an air-diaphragm-driven oscillation and harmonics from conventional sounding, keeping the default capability for discrete emergency warning intact as a backup capability.
The new discussion of separate EWS does not properly mention noise-cancelling headphones, or the ways an injected EWS needs to be 'notable' when typical noise-cancelling headphones are being used -- this was well-established and noted in the 2019 report. Some conclusions are carried over into the 2021 recommendation (e.g. the use of frequencies between 800 and 2000Hz with much of the 850Hz spread) but since this is a major "reason" for a fine new consultant-specified secondary horn system, it seems disingenuous at best to omit this as a design criterion.
The new discussion also pointedly omits the specific inclusion of both 'localizable' and Doppler-synthetic sound in the emergency signal, which would clearly give 'binaural trespassers' as good as possible 'imaging' (in the hifi sense) combined with something that, incredibly to me, was not in the flawed testing methodology although mentioned in the 2019 report in some detail: the use of synthetic Doppler in the signal to mimick the effect of repeated rapid acceleration (similar to a non-ramped triangle wave) which was identified as a major component of non-startle effectiveness not just in noticing the signal but reacting to it in the right ways, e.g. promptly clearing the track.
That the testing did not include the rather obvious intermediate stage of having volunteers in real-world multipath-reflection locations, with moving noise sources physically out of view at controlled distances and speeds, to confirm the dubious results of in-lab testing, tells me the wrong kind of consultants were being paid by the wrong class of PIs.
We should start a new thread referencing this specific subject, and either move the last few posts there or repeat/copy them in the new thread, as this has nothing to do with wheel-rail interactions and would only incidentally be found in a search.
Overmod Euclid So, in the discussion of the accident in that thread, we talked about inventing a new type of signal that would be better able to pierce through mental distraction. Maybe it would be super loud or super complex. It would be designed to address the general workings of human brain function and sound perception. It would not be any version of an air horn or a standard horn signal definition. It would be entirely new science of warning sound. The FRA report specifically avoided bold new approaches other than those practically achievable with air horns. It noted that frequencies higher than about 800Hz were less notable as 'emergency' signals and at the same time less directional, but also noted (ominously, in context) that current noise-cancelling headphones were quite efficient both in masking and ruining 'directionality' of noise below that frequency range. Much of the conclusion focused on what could be achieved with five horn chimes, the closest thing to a 'new type of signal' involving some form of overmodulation on the typical sound emitted from air-horn bells.
Euclid So, in the discussion of the accident in that thread, we talked about inventing a new type of signal that would be better able to pierce through mental distraction. Maybe it would be super loud or super complex. It would be designed to address the general workings of human brain function and sound perception. It would not be any version of an air horn or a standard horn signal definition. It would be entirely new science of warning sound.
The FRA report specifically avoided bold new approaches other than those practically achievable with air horns. It noted that frequencies higher than about 800Hz were less notable as 'emergency' signals and at the same time less directional, but also noted (ominously, in context) that current noise-cancelling headphones were quite efficient both in masking and ruining 'directionality' of noise below that frequency range. Much of the conclusion focused on what could be achieved with five horn chimes, the closest thing to a 'new type of signal' involving some form of overmodulation on the typical sound emitted from air-horn bells.
Overmod,
I don’t understand what you are referring to as an indication that FRA does not want to add secondary warning to the air horn. I did not make this clear, but what I have referred to as FRA developing a secondary warning sound in addition to the air horn is this, which is a two-part study linked by blue streak 1 above:
https://railroads.dot.gov/sites/fra.dot.gov/files/2021-03/AWD%20EWS%20Phase%202.pdf
In this report, it says this:
“The Federal Railroad Administration’s (FRA) Office of Research, Development and Technology is keen to assess the ways and means of saving more trespassers’ lives, and through this FRA-sponsored program, QinetiQ North America (QNA) carried out the research and development of alternative Emergency Warning Signal (EWS).
From September 2, 2014, to July 31, 2016, QNA and Harris Miller Miller & Hanson Inc. (HMMH) developed a secondary Emergency Warning Signal (EWS) generated by an Acoustical Warning Device (AWD) to supplement train horns. A secondary EWS has the potential to be more effective than a traditional train horn for warning trespassers on the right-of-way, especially when they are wearing earbuds or headphones.”
EuclidSo, in the discussion of the accident in that thread, we talked about inventing a new type of signal that would be better able to pierce through mental distraction. Maybe it would be super loud or super complex. It would be designed to address the general workings of human brain function and sound perception. It would not be any version of an air horn or a standard horn signal definition. It would be entirely new science of warning sound.
[The solution] would be fitted to locomotives in addition to the standard air horn. I have not fully read the linked PDFs yet, but from what I glean, it seems to me that it details precisely this new type of warning sound objective that we speculated about in the Ivy City fatality discussion.
The base horn is in current production; has been for well over a decade. Installation on existing locomotives with only a single valve might be addressed with suitable chokes in the manifolding or connections, something better than turning bells backward to 'approximate' 110dB in a synthetic forward plane. While there may turn out to be better solutions long-term, or resulting from a 'phase 2' of FRA research or comparable sources, this is a solution that could be implemented now and logically improved by currently practical means.
That is precisely the sort of thing that folks like Euclid could make a firm commitment to pursue through as many channels as they choose to open. And perhaps make a positive difference down the line in so doing.
blue streak 1 BaltACD My home is approximately 1/2 of a airline mile from the Old Main Line. The normal prevailing winds are generally from headings of 270 degrees to 360 degrees. The OML is at a heading of 180 degrees. Most of the time with the prevailing winds, while I can hear trains blowing for Main Street and Gaither Road crossing - they horn sounds distant. When the wind is blowing from about 120 to 240 degrees - the horn sounds like it is in my front yard. BALT. Thanks for that mention of wind direction. That may explain why some trains start my dogs howling at CSX & BNSF locos and other times do not. CN, NS, KCS locos not very often.
BaltACD My home is approximately 1/2 of a airline mile from the Old Main Line. The normal prevailing winds are generally from headings of 270 degrees to 360 degrees. The OML is at a heading of 180 degrees. Most of the time with the prevailing winds, while I can hear trains blowing for Main Street and Gaither Road crossing - they horn sounds distant. When the wind is blowing from about 120 to 240 degrees - the horn sounds like it is in my front yard.
My home is approximately 1/2 of a airline mile from the Old Main Line. The normal prevailing winds are generally from headings of 270 degrees to 360 degrees. The OML is at a heading of 180 degrees. Most of the time with the prevailing winds, while I can hear trains blowing for Main Street and Gaither Road crossing - they horn sounds distant. When the wind is blowing from about 120 to 240 degrees - the horn sounds like it is in my front yard.
The leaves on the trees are also a factor, I know I can hear the horns from CSX's W&A sub in the fall and winter.
Euclid But there have also been plenty of employee accidents caused by two train warnings sounding like one, and thus negating the warning effect to certain people, despite how loud and unmistakable the warnings are.
Source?
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
In the Ivy City accident discussion, we talked about the effect of two trains with engineers “laying on the horn” for a warning of impending death, and how each horn signal matched the other, and thus each covered up the existence of the other.
Since the victims were both facing the train approaching from their front, they were intently focused on the need to avoid its path. This distracted them from any focus on the train approaching from their back while they were fully in the path of that train.
Since, to their perception, both train signals matched each other, they attributed them only to the train they were paying attention to coming at them.
In the first place, “laying on the horn” is the wrong signal for such an emergency because it has no variation. That is why the proper signal is a series of short toots in rapid succession. Two train engineers sounding that signal are unlikely to ever get them to match in the timing interval or the magnitude of the toots. The signal was chosen precisely because it is unlikely to match any other ambient sound. In my opinion, railroad rules ought to make this point clear. Otherwise, the succession of toots seems rather undefined compared to other specified signal definitions. So, with that lack of specificity, it may be that some engineers would feel the laying on the horn would fit the rather broad definition of the “Danger to persons or livestock” horn signal that is defined by the series of random short toots.
So, in the discussion of the accident in that thread, we talked about inventing a new type of signal that would be better able to pierce through mental distraction. Maybe it would be super loud or super complex. It would be designed to address the general workings of human brain function and sound perception. It would not be any version of an air horn or a standard horn signal definition. It would be entirely new science of warning sound. It would be fitted to locomotives in addition to the standard air horn.
I have not fully read the linked PDFs yet, but from what I glean, it seems to me that it details precisely this new type of warning sound objective that we speculated about in the Ivy City fatality discussion. It is long overdue for the need, and may have been delayed by satisfaction with typical bells, whistles, and horns, and the belief that if a trespasser can’t hear that, it is their problem. Note that this new research focuses extensively on persons killed by trains while listening to music with earbuds. But there have also been plenty of employee accidents caused by two train warnings sounding like one, and thus negating the warning effect to certain people, despite how loud and unmistakable the warnings are.
Euclid That sounds like they are developing the kind of warning sound that would best alert a distracted person such as we discussed regarding the CSX Ivy City accident that killed the two CSX employees. That accident happened in a unique situation where two trains were sounding horn warnings to them at the same time, but they were facing one train approaching them and apparently believed the two train warnings they were hearing were coming from just the train they saw approaching them. They were clear of that train, but were fouling the track of the other train which was approaching from behind them. If the two trains were sounding radically different warning sounds, there would have been a better chance of the two victims distinguishing one train from the other, and thus realize there was a second train coming up behind them.
The acoustics in the area of F Tower, Ivy City where the CSX employees were struck is a virtual echo chamber. The railroads are bounded on both sides by buildings as well as having a highway running parallell to Amtrak. In addition to all those 'disrupters' to understanding where specific sounds are coming from - the CSX employees were also in the near vicinity of their own locomotives at the time. I don't believe it was ever reported if and where any wind was blowing from.
Never too old to have a happy childhood!
See my comments in the other thread ["Harrison's thread"], regarding what the Canadians now mandate as their horn design. I find it strange that research conducted as late as 2019 does not mention this.
It appears to me that the extra 'two bells' of the Canadian emergency modification could easily be adapted to produce the effects of options #9 and #10 in the FRA study (the two they identified as the most promising alternatives) as well as some of the proposed higher-harmonic amplification or high-speed overmodulation that were discussed. As far as I can see these would not add materially to the cost of the already-in-production Canadian horns.
People won't get out of the way of an electronic siren, combined with a Federal Q2B, and a pair of Grover air horns. All on a rolling light show.
I would opine that the subwoofer aspect actually would provide protection as it would be something a person would feel, not hear.
They also have to consider the location of the speakers/horns/etc - fire trucks are now mandated to have them mounted low on the front.
The effect on hearing for the crew should also be a factor.
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...
blue streak 1 FRA report of tests of acoustical warning devices. Guess that includes loco horns. This report says phase 1. That may be the reason that the Acela-2s being tested have the regular horn and the European style horn that we often hear in various U tube recordings ? Acoustical Warning Devices as Emergency Warning Systems, Phase 1 | FRA (dot.gov)
FRA report of tests of acoustical warning devices. Guess that includes loco horns. This report says phase 1. That may be the reason that the Acela-2s being tested have the regular horn and the European style horn that we often hear in various U tube recordings ?
Acoustical Warning Devices as Emergency Warning Systems, Phase 1 | FRA (dot.gov)
That sounds like they are developing the kind of warning sound that would best alert a distracted person such as we discussed regarding the CSX Ivy City accident that killed the two CSX employees. That accident happened in a unique situation where two trains were sounding horn warnings to them at the same time, but they were facing one train approaching them and apparently believed the two train warnings they were hearing were coming from just the train they saw approaching them. They were clear of that train, but were fouling the track of the other train which was approaching from behind them. If the two trains were sounding radically different warning sounds, there would have been a better chance of the two victims distinguishing one train from the other, and thus realize there was a second train coming up behind them.
Making round things
https://www.youtube.com/watch?v=pij4V-8kNNE
There is still hope. This is only Wheel Failure Investigation Program: Phase I. They have not yet solved the problem, but they do at least consider the method used by Rio Tinto that eliminates the problem for them.
Investigating the feasibility of using the Rio Tinto program to eliminate U.S. railroad wheel failures is an action item of this 5-year study by the FRA.
It is interesting that the report cites roadbed resiliency as being a possible factor explaining why wheel failures occur more frequently in the west than in the east. The correlation is that western railroads use more concrete ties versus wood ties, which are more common on eastern railroads. Concrete ties are less resilient than wood ties.
Another resiliency factor is the season. In winter, the ballast is frozen, so it is less resilient than in summer. This too correlates with wheel failures, which are more numerous in winter and spring than in summer and fall.
EuclidAs the FRA report says, the payoff for solving this wheel problem is not just longer lasting wheels, but also includes potential savings in rail wear and the cost of derailments. I suspect that the existing wheel design has been carefully developed with lots of little tweaks to get it just adequate to do the job, but nothing more. The design includes not only the physical shape of the wheel, but also many factors of manufacturing process, including metallurgy, hardness, malleability, etc. And these characteristics are not necessarily consistent throughout the wheel, but rather may be customized for applying to various features of the wheel. So with all of this tweaking, you end up with a lot of variables cooked up just the right way to work their magic of successful wheels. This objective would be difficult enough if it were locked in place and waiting for the miracle of success. But the objective is not locked in place. It is shifting with other changes such as higher axle loading, rail grinding, train operations, and all of the metallurgical factors affecting rail just as they affect the wheels. Suddenly, for some unknown reason, the magic formula for the wheel has become not quite adequate. And because the formula or design is so intricately complex with all of the tweaking, it poses so many theories of the cause of the trouble and possible remedies that the chance of solving the problem with just another little tweak is nearly impossible. Yet nobody wants to go beyond the smallest possible remedy because doing so would waste money. It would waste a lot of money because there are so many wheels affected by the change. So, instead, they will commission studies to look for possible remedies by a simple tweak. Therefore, fixing the problem is hampered by the same thinking that caused the problem. So, I conclude that the Rio Tinto solution to the U.S. railroad wheel problem is dead on arrival. Clearly the solution would succeed, but it is so much more than the one little tweak the industry is seeking.
I suspect that the existing wheel design has been carefully developed with lots of little tweaks to get it just adequate to do the job, but nothing more. The design includes not only the physical shape of the wheel, but also many factors of manufacturing process, including metallurgy, hardness, malleability, etc. And these characteristics are not necessarily consistent throughout the wheel, but rather may be customized for applying to various features of the wheel. So with all of this tweaking, you end up with a lot of variables cooked up just the right way to work their magic of successful wheels.
This objective would be difficult enough if it were locked in place and waiting for the miracle of success. But the objective is not locked in place. It is shifting with other changes such as higher axle loading, rail grinding, train operations, and all of the metallurgical factors affecting rail just as they affect the wheels.
Suddenly, for some unknown reason, the magic formula for the wheel has become not quite adequate. And because the formula or design is so intricately complex with all of the tweaking, it poses so many theories of the cause of the trouble and possible remedies that the chance of solving the problem with just another little tweak is nearly impossible. Yet nobody wants to go beyond the smallest possible remedy because doing so would waste money. It would waste a lot of money because there are so many wheels affected by the change. So, instead, they will commission studies to look for possible remedies by a simple tweak. Therefore, fixing the problem is hampered by the same thinking that caused the problem.
So, I conclude that the Rio Tinto solution to the U.S. railroad wheel problem is dead on arrival. Clearly the solution would succeed, but it is so much more than the one little tweak the industry is seeking.
What a crock - not worth all the wasted bits and bytes. Did you get that straight from Q?
As the FRA report says, the payoff for solving this wheel problem is not just longer lasting wheels, but also includes potential savings in rail wear and the cost of derailments.
We need a cost analysis of the two types of wheels - initial cost, and the cost of maintenance over the life of the wheel. Even the relative scrap value should be figured in.
There have been wrecks caused by wheel failures, which would tend to provide the cost of such incidents.
Then we compare. The single wear wheel may be cheaper in the long run. Or not.
According to the link in the top post, the majority of world railroads use Multiple-wear wheels, whereas the U.S. uses Single-wear wheels. Also, the report in the link says that Rio Tinto, which runs Multiple-wear wheels at higher wheel loading than U.S. practice, has no wheel failures. So their example offers proof that a wheel re-truing program would eliminate the wheel breakage plaguing U.S. practice.
The periodic wheel re-truing associated with Multiple-wear wheels, as practiced by Rio Tinto, would indeed require new infrastructure and operating specialists for application to U.S. railroads. I am sure the Multiple-wear wheels are more expensive as well.
It would be nice to find references to the wheel re-truing practices used by Rio Tinto, as it might be a good example of what could be applied to U.S. practice. Maybe the application of the wheel re-truing, as applied to U.S. practice could be farmed out to independent contractor service companies, such as is done with railroad wreck services.
There is definitely added cost to a wheel re-truing program, but it also comes with added benefit. However, the cost/benefit is a gamble with odds likely not agreed on.
Just one Lac Megantic style oil train wreck caused by a wheel failure will have the court studying this 20-30 years of wheel research that clearly identified the problem, but never solved it. That would be a financial risk, but the larger systemic risk would be to trigger the government into mandating new wheel standards.
Whales and flowerpots (to invoke infinite improbability).
Multiwear wheels are so because they are cast with different metallurgy and treatment to have a thicker rim, which is where the extra tare weight, rotational moment, etc. live. As Balt implies, this adds up to an enormous aggregate mass penalty (albeit a variable one as some percentage of the wheels presumably wear down to the condemnation limit) and very little time or effort would be saved in turning them in three-piece trucks in situ with an underfloor-lathe setup vs. just changing out wheelsets and bearings and then 'remanufacturing' in more-or-less interchangeable single-life units.
Now I among others have argued that this would be different if wheels with extended 'wear life' matching that of modern AP bearings with M-942 lubrication were used -- at present perfectly-serviceable bearings with long prospective safe wear life are destroyed in order to press condemned single-wear wheels on and off. Something I have never gotten good data on (and would like to see, if it exists in proper form) is whether running flat at various intensity short of the actual time of reprogoling in fact does damage the bearing in some way that increases risk of far more catastrophic failure than a rim breakage would cause.
I'm surprised no one has brought up the arguments pro and con about how the wheels handle high braking heat. In interchange service, braking has to be scaled to the 'least common denominator' of wear limit anyway, so the discussion usually turns to induced-crack propagation in the absence of widespread effective field NDT testing of wheels for induced or SCC damage. There has been plenty of discussion whether a 'magic wear rate' exists for multiple-wear wheels but I confess I'm far more concerned with "mistakes of assumption" in wheels than in rails, which can be and are readily and repeatedly tested analytically for stress-raising issues on a systematic and regular basis (at least by the sensible)...
In the old days when 'tired' wheels were legal, it made better sense to repeatedly reprofile 'faceted' wheels until, as on some classes of steam locomotive, the ride height had decreased by a number of inches. It looked for a while in the 1980s as if modern one-piece wheel mandates would apply to 'modern' reciprocating steam, particularly the ACE 3000 project, and there was as I recall specific discussion of how the drivers and spring rigging were designed for repeated multiple underfloor turnings.
Incidentally I was not aware that single-wear wheels couldn't be turned to remove surface damage... just that they couldn't be turned beyond the effective wear limit. Assessing this for a given 'flat' depth is not particularly rocket surgery, slthough it does require some care where and how you measure a few thicknesses...
BaltACD charlie hebdo Euclid Single-wear wheels are “run-until-failure”, with only one wheel truing operation allowed during the wheel life. The rest of the world uses Multiple-wear wheels which are intended to be re-trued on a regular basis. Changing the wheel standards from single-wear to multiple-wear wheels would definitely be a sweeping change. That would explain why one hears so many flat-spot wheels on our freight compared to ones in Germany. Apples and Oranges The only thing multiple wear wheels would accomplish is to increase the tare weight of a car by several hundred to 1K pounds, thus decreasing the amount of freight that the car can haul at capacity each trip. Germany has 2500 foot trains; USA is approaching 20K foot trains as normal.
charlie hebdo Euclid Single-wear wheels are “run-until-failure”, with only one wheel truing operation allowed during the wheel life. The rest of the world uses Multiple-wear wheels which are intended to be re-trued on a regular basis. Changing the wheel standards from single-wear to multiple-wear wheels would definitely be a sweeping change. That would explain why one hears so many flat-spot wheels on our freight compared to ones in Germany.
Euclid Single-wear wheels are “run-until-failure”, with only one wheel truing operation allowed during the wheel life. The rest of the world uses Multiple-wear wheels which are intended to be re-trued on a regular basis. Changing the wheel standards from single-wear to multiple-wear wheels would definitely be a sweeping change.
That would explain why one hears so many flat-spot wheels on our freight compared to ones in Germany.
Apples and Oranges
The only thing multiple wear wheels would accomplish is to increase the tare weight of a car by several hundred to 1K pounds, thus decreasing the amount of freight that the car can haul at capacity each trip. Germany has 2500 foot trains; USA is approaching 20K foot trains as normal.
Fig and prunes [since this is largely a forum for the elderly ]. Why would length of train result in more flat spots that continue uncorrected? Excessively long and heavy, slow trains running with "precision" are all part of a corporate policy of short-term profits and looting.
Euclid BaltACD charlie hebdo Euclid Single-wear wheels are “run-until-failure”, with only one wheel truing operation allowed during the wheel life. The rest of the world uses Multiple-wear wheels which are intended to be re-trued on a regular basis. Changing the wheel standards from single-wear to multiple-wear wheels would definitely be a sweeping change. That would explain why one hears so many flat-spot wheels on our freight compared to ones in Germany. Apples and Oranges The only thing multiple wear wheels would accomplish is to increase the tare weight of a car by several hundred to 1K pounds, thus decreasing the amount of freight that the car can haul at capacity each trip. Germany has 2500 foot trains; USA is approaching 20K foot trains as normal. It is not apples and oranges. Multiple wear wheels periodically have their treads re-trued in order to reestablish the proper tread/flange profile and eliminate surface defects such as flat spots, cracks, and residual stress that are induced as the wheels run in service. It is all of those defects that accelerate tread deterioration and causes the wheel to be condemned or to fail in service, sometimes with catastrophic results. Periodic re-truing of wheels offers the same benefit as periodic re-truing of rail. Whatever weight penalty there is in multiple wear wheels compared to single wear wheels, it is a tradeoff to the benefit of multiple wear wheels lasting longer than single wear wheels; and not causing train wrecks as they wear out, as is possible with single wear wheels.
It is not apples and oranges. Multiple wear wheels periodically have their treads re-trued in order to reestablish the proper tread/flange profile and eliminate surface defects such as flat spots, cracks, and residual stress that are induced as the wheels run in service. It is all of those defects that accelerate tread deterioration and causes the wheel to be condemned or to fail in service, sometimes with catastrophic results.
Periodic re-truing of wheels offers the same benefit as periodic re-truing of rail.
Whatever weight penalty there is in multiple wear wheels compared to single wear wheels, it is a tradeoff to the benefit of multiple wear wheels lasting longer than single wear wheels; and not causing train wrecks as they wear out, as is possible with single wear wheels.
That I am aware of, there is no existing infrastructure on the US carriers to permit for the routine truing of multi-wear wheels. How long would a car be out of service in having each of its 8 wheels set up in a appropriate lathe to have the wheels trued, versus the time required to to change out wheel sets?
To my mind, the fix, is not multiple wear wheels but increased used of WILD detectors and changing out WILD detected damaged wheel sets.
EuclidMy bet is that they will not admit to that failure, but will instead decide that the problem is so small that the best solution is to just live with it; no need to “reinvent the wheel,” they will say.
This would follow closely the "Pinto Principle," wherein the manufacturer decided it was cheaper to pay off lawsuits than it was to actually fix the problem.
Without a detailed cost analysis, though, we may never know.
Wheel manufacture - not US
https://www.youtube.com/watch?v=8hBeeZ1Pvsg
EuclidI wonder if some type of relatively rare anomalies in the practice of setting up brake service applications might explain why these VSR failures occur consistently, but so infrequently compared to the number of wheels in service.
I suspect there might also be a connection with flats; I don't know how carefully wheels are NDT-tested when the flats are trued out.
If you look at the metallurgy in crack propagation you'll get an idea of how difficult it might be to detect this particular thing with a running inspection: I think it's a bit like a collar-button abscess with the real damage invisible in a volume within the wheel difficult to 'visualize' on ultrasonic scan.
I'd at least look at the contemporary history of brakeshoe composition; it may be that some formulations intended to outgas less (and hence have lower tendency to runaway fade) might spot-overheat damaged tread adjacent to the 'depressed' rail/wheel contact zone.
Shadow the Cats ownerFrom reading that report it sounds like a triple failure. Improper metalurgy in the wheels. To much deferred maintance waiting until they are just at the minimum before doing anything to fix the issue. And the last one is not enough inspections to catch the problems before they fail. The railroads have gotten way to reliant on technology to catch problems. Wheel dynamic impact sensors to catch flat wheels hot box dectection by remote. So instead of having people look at things with the mark 1 eyeball they go by what the computer says is good. Doing things like that leads to massive problems down the line that tends to cost millions of dollars when they fail. We have all heard it that the carmen are under pressure to get the trains out of the yard. So instead of fixing them properly they say they are good and pray they make it to the next 1000 mile inspection point. You are just lucky that PSR hasn't caused a major TIH spill in a major city yet. The odds will catch up to the penny pinchers in the Boardrooms sooner than later and when it does I do not want to be a shareholder in the company it happens to be with.
How many truck accidents are there yearly because of unsafe, under standatd maintenance are there vs. train derailments because of your perception of railroad maintenance?
The Mark I eyeball is not as good a hidden defect detector as you may think it is.
https://www.fmcsa.dot.gov/safety/data-and-statistics/large-truck-and-bus-crash-facts
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