charlie hebdoIn terms of safety, I'm not sure the filler needs to come to the top of the railhead. Rather the ones I see (on a very busy heavy rail line) slant down, more or less parallel to the flange outline.
It is correct that this could be shy -- even an inch or two shy -- of being 'perfectly level' with the railhead; it is even relatively unlikely that the inch or two of ice or dirt that might accumulate in the resulting recess would pose much more derailment risk than similar accumulation in the flangeway of a crossing with the HDPE strip fillers.
It will literally take an act of Congress, or some scheme that caps or removes railroad liability for accidents related to or arising out of the full fullers, to get them established at crossings. I don't blame either the railroads or the AAR for fighting to ensure they stay out of becoming unfunded mandates or assumable risks for railroad companies.
charlie hebdo BaltACD Euclid ... However the rail transit industry apparently has accepted the concept and applied it on a widespread basis. Perhaps they may look at it differently than does the heavy rail industry because transit is public sector, and heavy rail is private sector. Rail Transit is not running 15K foot trains at 60 MPH. Derail a transit car or two is very different than derailing a freight train that can be hauling everything from 'air' to bulk commodities to methylethyldeath. Such a derailment can involve 30 - 60 or more cars. Given the weight similarity between most freight cars and transit, which is huge when loaded, the freight cars are even less likely to be derailed. Your argument is illogical contrafactual and an example of fear-mongering. Freight Ines have plenty of derailments and how many are caused by crossing impediments? Of course they do manage to collide with each other all over and still have time to hit vehicles and pedestrians at those pesky crossings.
BaltACD Euclid ... However the rail transit industry apparently has accepted the concept and applied it on a widespread basis. Perhaps they may look at it differently than does the heavy rail industry because transit is public sector, and heavy rail is private sector. Rail Transit is not running 15K foot trains at 60 MPH. Derail a transit car or two is very different than derailing a freight train that can be hauling everything from 'air' to bulk commodities to methylethyldeath. Such a derailment can involve 30 - 60 or more cars.
Euclid ... However the rail transit industry apparently has accepted the concept and applied it on a widespread basis. Perhaps they may look at it differently than does the heavy rail industry because transit is public sector, and heavy rail is private sector.
However the rail transit industry apparently has accepted the concept and applied it on a widespread basis. Perhaps they may look at it differently than does the heavy rail industry because transit is public sector, and heavy rail is private sector.
Rail Transit is not running 15K foot trains at 60 MPH. Derail a transit car or two is very different than derailing a freight train that can be hauling everything from 'air' to bulk commodities to methylethyldeath. Such a derailment can involve 30 - 60 or more cars.
Given the weight similarity between most freight cars and transit, which is huge when loaded, the freight cars are even less likely to be derailed. Your argument is illogical contrafactual and an example of fear-mongering.
Freight Ines have plenty of derailments and how many are caused by crossing impediments? Of course they do manage to collide with each other all over and still have time to hit vehicles and pedestrians at those pesky crossings.
As long as 'you and your device' are willing to accept total liability should your device cause a derailment and post a bond to cover the potential - have at it and have fun! $100M sound like a potentially adequate bond.
Never too old to have a happy childhood!
In terms of safety, I'm not sure the filler needs to come to the top of the railhead. Rather the ones I see (on a very busy heavy rail line) slant down, more or less parallel to the flange outline.
EuclidIt is not even remotely similar or even analogous to running over a tire with a train.
In practice, of course, tires use internal pressure in the chamber (which is why they're called 'pneumatic tires') and rely on controlled deformation in the side walls more then deflection in the tread. This was not entirely the case for the "Micheline" approach, which used controlled deflection of the tread to center and guide the wheel -- an approach that works well for short times even on modern tires, as a friend of mine who owned a '70s Chevy Nova found out: if the vehicle track measured across tire centers is the same as the gauge, and the tires are slightly deflated so the tread can become concave when loaded on a rail, a profound self-steering effect develops even up to high speed, similar to that of a coned wheel but acting in both directions and with built-in damping of oscillations. Michelin backed this up with a flange but with the assumption it would only be 'for emergencies' or when negotiating sharper curves, and had it worked dynamically in groups of eight or ten the way it did in theory, it might have revolutionized light vehicles on even fairly crappy jointed rail. In practice the things bounced like basketballs when excited by low joints, especially if there were a resonance in the suspension related to the 39' spacing (like that in the Alco Hi-Ads susceptible to harmonic rock).
Few of the actual effects in tires are common to actual crossing fillers, including those cited by Euclid. Nor, I think, is the material in current tire treads common to extruded fillers. However, bending stresses in the shapes shown in Euclid's reference material might be interesting in producing permanent deformation and stress-raised cracking if the material's glass transition is close to something that might be encountered environmentally... which is seen in [/quote]Nor is is similar to the o-ring failure on the Space Shuttle.[/quote]Of course it is, or rather would be if the crossing fillers, as in the Shuttle ring case, had the glass transition temperature set unfortunately high. Interestingly enough Morton Thiokol had foreseen this issue fairly carefully (as high, not low temperatures were the danger) and had a hard engineering note that UNDER NO CIRCUMSTANCES were the boosters to be flown under about 41 degrees ambient.
It was 21 when the politically-motivated Challenger launch was attempted.
Recently there was a discussion of the 614T testing conducted in the mid-80s for American Coal Enterprises, in which Ross recounted quite a bit of experience at -35F. One place you can bet ambient temperature will be effectively heat-sinked is in components in contact with continuous steel rail. That will be one sidewall of the 'chamber' form. It had better remain amorphous and fully elastic below that temperature range...
Incidentally the range of deflection is probably less that an inch, but it's closer to the gauge side of the rail than the center of the extrusion, so either the chamber has to be asymmetrical or the bending greater on the gauge-side wall. And the deflection is determined by the maximum tolerable under bicycle or wheelchair spot pressure -- or by keeping the section from deflecting measurably at all under that load -- preserving the lowest possible resistance to deflection that can be tolerated by those vehicles and their users.
I also find it almost imcomprehensible that the face of such a filler would support, let alone sustain, combustion from a source as small and transient as a cigarette butt (or, now perhaps as likely in California, a marijuana roach). Or in fact, given the mass in the bearing face and contact with the heat sink of the rail, that even pouring lighted gasoline on it in an accident would cause more than surface char damage. Of course, the world is full of idiot designers who might leave flame-retardancy out of their mixture or surface treatment ASSuming it couldn't possibly see heat sources in use...
EuclidYou must be referring to this from one of my posts on the previous page: Quote: “Tried multiple times & fails all the time...could only be used in warm weather states and cigarettes set the pliable flangeway filler on fire.” Rail seal products are made from thick rubber just like tires, and that is why tires have been tried multiple times and fail all the time because they can't be used in cold weather and cigarettes set them on fire.
Quote: “Tried multiple times & fails all the time...could only be used in warm weather states and cigarettes set the pliable flangeway filler on fire.”
Rail seal products are made from thick rubber just like tires, and that is why tires have been tried multiple times and fail all the time because they can't be used in cold weather and cigarettes set them on fire.
Yes, I was referring to your language following the quote you attributed to MC.
Your language appeared to be intentionally facetious, so I thought you might appreciate a similarly spirited reply.
The "normal" use of tires in which they are successfully applied being other than the application we are discussing here.
Sticking my head further in the barrel, It wouldn't surprise me that if a flangeway was filled with combustable material, and a wind-whipped cigarette butt ignited those materials, a fire sufficient to damage the elastomer in the flangeway might result.
It's not so much that you have a "burning gasket" as you might have a flame damaged gasket. One that might not stand up to mechanical abuse...just something to think about
Having personal experience with moving joints employing similar materials in both commercial buildings and parking structures, I can tell you from experience that this risk is genuine.
Euclid... However the rail transit industry apparently has accepted the concept and applied it on a widespread basis. Perhaps they may look at it differently than does the heavy rail industry because transit is public sector, and heavy rail is private sector.
My understanding is that both the SFRS and FF are in need of regulatory approval for use in heavy rail systems. I do not know where they are at in the process of approval, but the resistance is likely to be much greater with FF because it actually fills the flangeway, and must be compressed by the passing train.
However, I find no evidence that either product is being stopped by a failure to successfully perform their intended function. So I doubt that either flammability or temperature performance are practical obstacles to widespread use.
But apparently what is an obstacle is railroad industry resistance to the concept because it reduces the extra space around the actual flangeway envelope. Apparently, the industry completely rejects the FF out of fear that it could cause a derailment.
Convicted One Euclid It is not even remotely similar or even analogous to running over a tire with a train. I thought that the logic was roughly approximate to your submission that " tires have been tried multiple times and fail all the time because they can't be used in cold weather "
Euclid It is not even remotely similar or even analogous to running over a tire with a train.
I thought that the logic was roughly approximate to your submission that " tires have been tried multiple times and fail all the time because they can't be used in cold weather "
You must be referring to this from one of my posts on the previous page:
Quote:
“Tried multiple times & fails all the time...could only be used in warm weather states and cigarettes set the pliable flangeway filler on fire.”
***************************************************************
The word "Quote" at the start of the start of the part in red means the part in red is quoted from MC from around page 1 or 2.
I don't know whether it is accurate or not, but I doubt it. I have seen these products in photos and videos, and they look like very heavy rubber like that of rubber tires for cars and trucks. I do not see those tires being set afire from cigarettes. Nor do I see them being only useble in warm weather. Therefore, I don't believe the claim that these flageway products have never been made workable because of catching fire from cigarettes or not working in cold weather.
Convicted One Overmod I personally can't imagine any problem in developing a combination of face material, core foam, and blowing-agent compositions and pressures that would not produce a reliable, UV- and contaminant-resistant strip that would bottom-anchor to a "legal" HDPE or whatever flangeway bottom filler across the width of a crossing (with approach nose pieces either end) which would reliably compress away in flange contact but not substantially under transient bicycle content or even sustained contact by even suicide-minded scooter pilots. While Euclid's sources may be selective in addressing how they handle their materials selection and fabrication, I'm sure you looked at the illustrations that Euclid linked to. With the hollow cell that deforms under the weight of the rail wheel, but not under the weight of a scooter. I'd be really, truly amazed if someone could develop an elastomeric that would withstand thousands of cycles per week in freezing temperatures, for very long. Add to that, the material must remain rugged on hot summer days, that is going to be a pretty remarkable material.
Overmod I personally can't imagine any problem in developing a combination of face material, core foam, and blowing-agent compositions and pressures that would not produce a reliable, UV- and contaminant-resistant strip that would bottom-anchor to a "legal" HDPE or whatever flangeway bottom filler across the width of a crossing (with approach nose pieces either end) which would reliably compress away in flange contact but not substantially under transient bicycle content or even sustained contact by even suicide-minded scooter pilots. While Euclid's sources may be selective in addressing how they handle their materials selection and fabrication,
I'm sure you looked at the illustrations that Euclid linked to. With the hollow cell that deforms under the weight of the rail wheel, but not under the weight of a scooter.
I'd be really, truly amazed if someone could develop an elastomeric that would withstand thousands of cycles per week in freezing temperatures, for very long.
Add to that, the material must remain rugged on hot summer days, that is going to be a pretty remarkable material.
Regarding what I highlighted in red above:
The hollow cell deforms under the force of the wheel weight, but the range of deformation is limited to only the depth of the wheel flange, or about one inch. So the hollow elastomer form is compressed by the wheel load, but the deformation is stopped after progressing just one inch. And at that point, the hollow voids in the elastomer extrusion are not even fully collapsed.
So while the wheel weight load to the rail may be teens of tons, the actual loading to the elastomer flangeway filler may be only a few hundred pounds. And that loading is on the relatively compressible, hollow void structure within the extruded form of the flangeway filler.
It is not even remotely similar or even analogous to running over a tire with a train.
Nor is is similar to the o-ring failure on the Space Shuttle.
If you design it like a tire, it has to do what a tire does. Interestingly there is a long and fascinating history of various ultimately-defective attempts to get tires to run compatibly at high speed over jointed rail with self-guarding frogs, which does have technological solutions but not commercial ones.
Anyone who looks at this problem will comprehend that a single central chamber will not succeed under the multiple stressing conditions: the 'face' has one set of concerns, and the bearing foam in the core very different ones. That battle was partially fought and lost with foam-filled ag and off-road tires, but then fought and won with the last generation of run-flats in European practice.
In any case, much of the argument appears to be predicated on the quaint American notion that the actual filler to TOR needs to be the 'only' part of the whole solution, that it needs to be 'fire and forget' in deployment, and that it needs to be designed and placed to be permanent. None of my own designs (since I was about 16) have suffered from those misconceptions, and I would like to think that Euclid's discussed ones won't.
As previously noted, the highway authority and not the railroad is responsible for the whole cost of the filler system, whether or not they delegate its provision or maintenance to railroads. They are also responsible for periodic maintenance and its effective documentation, and timely forwarding if defects or impending/overt failure, as necessary; it is ridiculous to have a railroad mandated to do this system-wide when local resources can do it 'distributed' (and use a government, socially-funded, repository as a clearinghouse both for information and cumulative data storage)
In my designs at least the 'face' is not continuous: there are periodic screw attach points molded 'through' that are overdesigned not to be fatigue or exposure fail points, and the strip is held to the underlying HDPE or whatever with security screws in addition to aggressive assisted with surface activation. Removal is relatively simple; replacement either taps back into existing holes or, with only slight and logically-understandable 'displacement' along the flangeway, self-tapped into new areas of HDPE. If you make the core foam a highly contrasting color, or put in material that visibly extrudes colored indicator through any crack or candalism damage, even casual inspection by town employees or an 'informed' public will give perfectly adequate warning of a need to repair or replace.
OvermodI personally can't imagine any problem in developing a combination of face material, core foam, and blowing-agent compositions and pressures that would not produce a reliable, UV- and contaminant-resistant strip that would bottom-anchor to a "legal" HDPE or whatever flangeway bottom filler across the width of a crossing (with approach nose pieces either end) which would reliably compress away in flange contact but not substantially under transient bicycle content or even sustained contact by even suicide-minded scooter pilots. While Euclid's sources may be selective in addressing how they handle their materials selection and fabrication,
Overmod Convicted One Take two identical rubberbands. Put one in the freezer over night, and then compare the two the following morning. Or for that matter use certain common O-rings...
Convicted One Take two identical rubberbands. Put one in the freezer over night, and then compare the two the following morning.
Or for that matter use certain common O-rings...
For those who may not remember:
https://www.youtube.com/watch?v=raMmRKGkGD4
Greetings from Alberta
-an Articulate Malcontent
Convicted OneTake two identical rubberbands. Put one in the freezer over night, and then compare the two the following morning.
Seriously, the reason MC is 'important' here is not because of some appeal-to-authority fallacy but because he knows the law and others don't. That counts for a great deal more than an acquired knowledge of advanced polymer chemistry and preparation.
One might as gainfully read John White's description of rubber car springs from even the era before 1834 ... which neatly contains all the pratfalls so far named in this thread ... and then look at the solutions for air-suspension bag springs and rubber isolators and snubbe in the railroad industry in the past half-century or so.
I personally can't imagine any problem in developing a combination of face material, core foam, and blowing-agent compositions and pressures that would not produce a reliable, UV- and contaminant-resistant strip that would bottom-anchor to a "legal" HDPE or whatever flangeway bottom filler across the width of a crossing (with approach nose pieces either end) which would reliably compress away in flange contact but not substantially under transient bicycle content or even sustained contact by even suicide-minded scooter pilots. While Euclid's sources may be selective in addressing how they handle their materials selection and fabrication, it should not be difficult to evolve a standards-type set of test requirements for a 'safe' device of the kind, which would suit agencies and Congressional committees well enough to "harmonize" the law with certain perceived 'social' improvements...
EuclidRail seal products are made from thick rubber just like tires, and that is why tires have been tried multiple times and fail all the time because they can't be used in cold weather
Run over an automobile tire with a 100 car loaded coal train, and then (try to) put it on your car and drive with it.
And then do the same thing with a tire that has sat outside over night at 20 degrees below zero, and note the difference.
As bad as the first tire is, the second will be far worse.
Take two identicle rubberbands. Put one in the freezer over night, and then compare the two the following morning.
tree68 charlie hebdo I strongly believe that trained and experienced experts' opinions are generally the ones that take precedence That's why we tend to take MC's word for it.
charlie hebdo I strongly believe that trained and experienced experts' opinions are generally the ones that take precedence
That's why we tend to take MC's word for it.
And that's why you snipped and pasted only the first part of my comment and ignore the posts of Euclid. No one is infallible and we all have an axe to grind: myself, you and MC, though he is the only one with a stake in the game.
charlie hebdoI strongly believe that trained and experienced experts' opinions are generally the ones that take precedence
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...
Euclid SD70Dude charlie hebdo Perhaps you should ask MC (or whoever said that) why he posted an unsubstantiated opinion as though it were an established fact? It is well known that MC has a job involving track maintenance. By the sounds of it he had some first-hand experience with the stuff. If cigarette butts set it on fire, what the heck is it made of? Nitrate film!? Quote: “Tried multiple times & fails all the time...could only be used in warm weather states and cigarettes set the pliable flangeway filler on fire.” Rail seal products are made from thick rubber just like tires, and that is why tires have been tried multiple times and fail all the time because they can't be used in cold weather and cigarettes set them on fire.
SD70Dude charlie hebdo Perhaps you should ask MC (or whoever said that) why he posted an unsubstantiated opinion as though it were an established fact? It is well known that MC has a job involving track maintenance. By the sounds of it he had some first-hand experience with the stuff. If cigarette butts set it on fire, what the heck is it made of? Nitrate film!?
charlie hebdo Perhaps you should ask MC (or whoever said that) why he posted an unsubstantiated opinion as though it were an established fact?
Perhaps you should ask MC (or whoever said that) why he posted an unsubstantiated opinion as though it were an established fact?
It is well known that MC has a job involving track maintenance. By the sounds of it he had some first-hand experience with the stuff.
If cigarette butts set it on fire, what the heck is it made of? Nitrate film!?
+1
I strongly believe that trained and experienced experts' opinions are generally the ones that take precedence. But sometimes well-meaning folks are so entrenched in their positions that they can't accept change and can only make rather silly. comments.
BaltACD charlie hebdo Perhaps you should ask MC (or whoever said that) why he posted an unsubstantiated opinion as though it were an established fact? Salesmen for products make many 'claims of fact' (their words) about their product - real world experience with those products in many cases refute those 'facts' and change them to bald faced lies. As in everything involving humanity - buyer beware.
Salesmen for products make many 'claims of fact' (their words) about their product - real world experience with those products in many cases refute those 'facts' and change them to bald faced lies. As in everything involving humanity - buyer beware.
Sure there are bogus products that are marketed as lies. But this rail seal line of products seems to be in widespread use with extremely clear videos and illustrations explaining the purpose and installation details. There are also many posted photographs of them installed on active grade crossings. They are manufactured by companies that make other railroad related products. And the explanations of how they work is not at all hard to believe or comprehend.
So when somebody says this, it does not seem to fit the pratical reality:
I don't doubt that there were trials and failures. Temperature performance of the rail seal material was probably tested extensively to get it to work with all conditions. But I doubt that temperature and cigarettes were a showstopper as the above comment implies.
charlie hebdoPerhaps you should ask MC (or whoever said that) why he posted an unsubstantiated opinion as though it were an established fact?
Paul of Covington charlie hebdo Bucky: That makes a lot of sense to me, as an amateur. I wonder what the real objections would be? Cost? Maintenance? Arrogance of ownership? This was Mudchicken's answer back in the first wheelchair thread on Aug 14: Paul of Covington mudchicken Mod: anything placed above the top of rail is a bozo no-no. (FRA/CaPUC/AREMA)....the same goes for any striping in the foul zone How about filling the gaps with something resilient that would support the weight of people but squish down under the rail traffic? I seem to remember seeing that somewhere, but I'm trying to remember where. Maybe it was streetcar tracks. Tried multiple times & fails all the time...could only be used in warm weather states and cigarettes set the pliable flangeway filler on fire. FRA flangeway rules needed a special exemption before the stuff was used. ______________ (edit): I tried copying the post and pasting it here. It may not be obvious, but the last reply is Mudchicken's answer. Here is the thread: http://cs.trains.com/trn/f/111/t/283776.aspx
charlie hebdo Bucky: That makes a lot of sense to me, as an amateur. I wonder what the real objections would be? Cost? Maintenance? Arrogance of ownership?
Bucky: That makes a lot of sense to me, as an amateur. I wonder what the real objections would be? Cost? Maintenance? Arrogance of ownership?
This was Mudchicken's answer back in the first wheelchair thread on Aug 14:
Paul of Covington mudchicken Mod: anything placed above the top of rail is a bozo no-no. (FRA/CaPUC/AREMA)....the same goes for any striping in the foul zone How about filling the gaps with something resilient that would support the weight of people but squish down under the rail traffic? I seem to remember seeing that somewhere, but I'm trying to remember where. Maybe it was streetcar tracks.
mudchicken Mod: anything placed above the top of rail is a bozo no-no. (FRA/CaPUC/AREMA)....the same goes for any striping in the foul zone
How about filling the gaps with something resilient that would support the weight of people but squish down under the rail traffic? I seem to remember seeing that somewhere, but I'm trying to remember where. Maybe it was streetcar tracks.
Tried multiple times & fails all the time...could only be used in warm weather states and cigarettes set the pliable flangeway filler on fire. FRA flangeway rules needed a special exemption before the stuff was used.
______________
(edit): I tried copying the post and pasting it here. It may not be obvious, but the last reply is Mudchicken's answer. Here is the thread:
http://cs.trains.com/trn/f/111/t/283776.aspx
A “rail seal” is comprised of two slightly different rubber extrusions, each placed against the side of the rail in a grade crossing. The difference in the two extrusions is that the one on the gage side of the rail contains a flangeway as part of the extrusion, and other one on the field side of the rail has its top surface flush with the top of the rail head.
The main purpose is to seal the rail against intrusion of water, snow, dirt, and trash, which otherwise can get under the rail and into the ballast, which then can foul the ballast and impede drainage. So a rail seal is basically a rubber gasket.
As a train passes over a crossing, there is often up and down movement of the rail bed as the crossing bed remains stationary. The flexible nature of the rubber rail seal accommodates the track movement while maintaining a tight seal between the moving rail and the stationary crossing bed.
In my most recent post just above, I described two products capable of reducing the flangeway hazard. One is the SHALLOW FLANGEWAY RAIL SEAL. As I understand it, this is a rail seal with the shallowest flangeway that will not interfere with the flange. As I understand it, this SFRS is just now being introduced, and may need regulatory approval.
The other of the two products I am describing is what I call a FLANGEWAY FILLER (FF). As I understand it, the FF is not approved for use in heavy rail system grade crossings, but only used for transit rail crossings.
Therefore, the main product that promises to be the solution to flangeway dangers of heavy rail systems is the SHALLOW FLANGEWAY RAIL SEAL. It differs from the basic rail seal by having a shallower and wider flangeway than does the basic rail seal.
I find nothing to verify that assertion quoted above that says about these rail seal products that they have been:
These products are being manufactured and sold, and seem to be in widespread use. The SHALLOW FLANGEWAY RAIL SEAL may not be in use, but it is just a new version of the basic RAIL SEAL, and they use the same pliable rubber material as will the SHALLOW FLANGEWAY RAIL SEAL. So what is it exactly that has been “tried many times and fails all the time” ?
Yeah, that covers it. As Don Oltmann has said about rail culture. "We don't it that way because we've always done it that way." And the corollary: "Any idea to the contrary? Wrong!!!"
_____________
"A stranger's just a friend you ain't met yet." --- Dave Gardner
The alternative concept to the SHALLOW FLANGEWAY RAIL SEAL (SFRS) is the FANGEWAY FILLER (FF). With FF, when no train is passing, the flangeway is 100% filled, flush with the crossing surface and rail head. In effect, there is no flangeway when no train is passing. So bicycles and wheelchairs will be unaffected by a flangeway.
However, the flangeway filler is resilient, so as a train passes, its flanges can depress the filler and make room for its flanges to pass. After a flange passes, the filler rebounds to its normal full elevation. This depress-and-rebound action occurs with the passage of each wheel. Because the train is so much heavier than road vehicles and further concentrates that weight onto each flange, the train will be able to depress the flange filler material, whereas road vehicles will not compress it at all. With so much weight difference to work with, the train flanges will be able to completely depress the filler with no chance at all of lifting the wheels off of the rail and thus disengaging a flange.
Therefore, regarding any goal of a “perfect” solution, the FF is closer to perfection than is the SFRS. The main difference is that FF prevents the flangeway from catching a bicycle wheel and causing it to run in the flangeway and thus veer off track to the course of the bicycle. The SFRS cannot eliminate this danger to bicycles, but it does eliminate the danger of bicycles getting a wheel stuck in a flangeway. So the only remaining part of the hazard is to pedestrians stepping on the rail, which is the smallest component of the overall hazard involving pedestrians on foot, on bicycle, or in wheelchair.
From what I gather, FF is widely used and accepted for transit railroads but not for heavy rail freight railroads. One reason given is that freight trains are too heavy for the filler material, and this quickly wears out the filler. However, this seems like nonsense because freight trains or transit trains can only depress the filler to the depth of their flanges, and both do so easily with their inherent weight, so there is no way a freight train can harm the flange filler that cannot be harmed by a transit train.
So, I assume the actual reason is that the railroad industry cannot countenance the idea of closing the flangeways at crossings and then forcing the trains to open them in order to pass. This rejection of the principle may be based on the practical experience of flangeways getting filled with dirt or ice to the point where opening them with a train is not 100% feasible. Flangeways filled with ice or dirt are known to derail trains. So, apparently the common thinking is that flangeways must be kept clear out of respect to the flange.
But flangeway fillers are not dirt or ice, and they have been proven to reliably yield to the weight of transit trains, so why can’t they do likewise with freight trains? If there is a practical reason, I have not heard it. But perhaps the cultural reason is enough to prevent flangeway fillers to be used for freight trains.
In any case, SFRS minimizes the flangeway size to the point of being practically safe without obstructing any of the flange path. However, it does reduce the respect to the flange by reducing the margin of extra space in the flangeway. That extra space is used to accommodate ice and dirt entering the flangeway before it accumulates to the poing of fouling the the actual flange path. So the extra space in the flangeway buys time before ice melts or dirt needs to be removed. With the SFRS, any accumulation of ice or dirt immediately fouls the flange path. So, for that reason, the SFRS appears to be a non-starter.
But there is another side of the coin with this issue. Ice fouling is much more common than dirt fouling. Dirt fouling has practical solutions that can eliminate the occurrence. But ice fouling is part of weather. The only way to eliminate it would be to heat the crossing. But here is the key. With the SFRS, ice fouling begins immediately upon formation of ice. There is no extra space in the flangeway to fill with ice before fouling the flange path. So ice will begin flange contact once it fills the flangeway to say ¼ inch above the flangeway floor.
Ice is brittle and the flangeway floor of SFRS is somewhat flexible even though it is not made to yield to flange interference as is the case with the Flangeway Filler (FF). When the ¼ inch of ice buildup on the SFRS floor reaches the height of the flange tip, the flange will depress the ice layer which is supported on a flexible floor of the SFRS. This interfering flange contact will depress the ice layer as it also bends it, thus causing it to easily fracture and disintegrate. So the shattered ice layer will be ejected from the flangeway by the passing flanges. This effect of immediately clearing ice from flangeways will also apply to clearing dirt. Either material will be cleared by the flanges because the clearing begins when the layer of the interfering material is very thin and supported on a flexible floor of the flangeway.
Therefore, while there is a customary belief that flangeways need extra space to hold debris while provding clearance to the flange; there is a counterpoint that eliminating the extra space makes the flangeway self-cleaning.
Convicted One BaltACD .Ah yes - The disabled need to be vetted, supervised and trained more effectively. From the post you were responding to: Perhaps better vetting of caregivers is an answer?
BaltACD .Ah yes - The disabled need to be vetted, supervised and trained more effectively.
From the post you were responding to: Perhaps better vetting of caregivers is an answer?
In as much as the incident that has generated this thread was from a diabled individual without caregiver - it applies to the disabled individual.
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