My immediate reaction is that they are underestimating the cracking problem.
It's not what it's cracked up to be
https://www.staradvertiser.com/2022/11/19/hawaii-news/plan-awaits-to-fix-cracks-in-rail-station-supports/
I happen to agree with Zugman in the case of this specific rail line. From the photo, there ap;ears plenty of real-estate for two simple crossovers instead of a sizzors arrangement. Sure, in NY and Chicago, most places there is not sch an option, and perhaps the designers of this system somply wished to mimic "the established."
HART rail lacks funds studying shorting over 1 mile.
HART Board Approves A New Honolulu Rail Plan For A Shorter Route (msn.com)
Erik_Mag blue streak 1 Only 1 or 2 degree errror that the botttom of the rails sit on may be enough to tilt the rails in 1/2 inch? 2 degrees would tilt an 8" tall rail by ~1/4 inch, so with both rails with an extra 2 degree cant towards the center would reduce gauge by 1/2". I was about to write that you were a factor of too low and then remembered there were two rails involved.
blue streak 1 Only 1 or 2 degree errror that the botttom of the rails sit on may be enough to tilt the rails in 1/2 inch?
Only 1 or 2 degree errror that the botttom of the rails sit on may be enough to tilt the rails in 1/2 inch?
2 degrees would tilt an 8" tall rail by ~1/4 inch, so with both rails with an extra 2 degree cant towards the center would reduce gauge by 1/2". I was about to write that you were a factor of too low and then remembered there were two rails involved.
Erik: Thanks for the math. that correction certainly falls into what causes the too close.
Former Car Maintainer Now, the tracks are too narrow..... https://www.staradvertiser.com/2022/02/25/breaking-news/new-mismatch-problem-emerges-for-oahus-rail-wheels-track/
Now, the tracks are too narrow.....
https://www.staradvertiser.com/2022/02/25/breaking-news/new-mismatch-problem-emerges-for-oahus-rail-wheels-track/
I guess they got the Hawaiian Labor unions to sign off on using out of state welders to fix an avoidable mismatch between frog and wheel.. https://www.staradvertiser.com/2021/12/09/hawaii-news/new-plan-to-fill-gap-between-rail-wheels-and-track/
The document above says that the 1/2 inch of added material will Gradually wear away when wider wheels are added. Good luck with that.
Widening of wheel flange from 4.75" to 5.28", welding and grinding of existing frogs per diagrams, contained in 103 page report. No bidders on welding. https://www.civilbeat.org/2021/11/hart-has-a-plan-to-fix-the-rail-tracks-but-lacks-welders-to-do-the-work/
dpeltier After staring at both photos for long enough I've almost started to believe that I understand the issue. Because things are so cramped, the only place where thete is room for a conventional guardrail is on the straight side of the mainline frogs. All other movements rely on "self-guarded" frogs. The way a self-guatded frog works is as follows: if the flange is riding hard up against the gauge face of the rail, then the outside edge of the wheel tread is pushed out over the field face of the rail. A little raised lip* in the casting on the field side of the rail will nudge the outside edge of the tread over, ensuring that the flange does not impact the point of the casting or, worse, go down the wrong side of the point and lead to a derailment. However, this relies on the wheel being wide enough for the outside part of the wheel to impact that lip. If the distance from the gauge face of the rail to the raised lip is greater than the width of the wheel, then the wheel will never nudge against the lip and the wheel will not be steered correctly. So when articles talk about the "wheel" or "wheel flange" being too narrow, they mean that the wheel itself is too narrow (where width is meausred parallel to the axle). When they talk about the "rail" being too "wide", they mean that the distance from the gauge face to the raised gauard is too wide. When they say that the problem only occurs for movements on the diverging route, this is correct - because the straight routes have proper guard rails opposite the frogs, and don't rely on self-guarding features of the casting. Note that when I say "gauge face of the rail", I really mean "the face of the casting's flangeway that corresponds to the gauge face of the rail leading into the casting for the route being taken." To complicate things a bit - you can see from the shiny wear marks in the photos that these are all flange-bearing frogs. (Probably to improve ride comfort, reduce noise, and tminimize impact loads on a very stiff direct-fixation track.) I don't think this fundamentally has anything to do with the underlying problem, but it might be related to why they have imposed a slow order on the STRAIGHT route (if indeed that is reported accurately). With a load-bearing flangeway, it might be that unusual wear or damage to the point is judged to introduce risk into the tracking of wheels traveling on the straight route, even if they are properly guarded? Or maybe there's something else at work. And welding up the lip to make it thicker could well be effective at solving the problem - no different than building up a worn tread or point on any other frog - but not a cheap fix! Or possibly I have missed the point completely. * Footnote: the raised lip on a self-guarded frog seems to be the one piece of trackwork that doesn't seem to have an assigned name or slang term. At.least, I've never heard or seen one. Anyone else? If not perhaps we need to make one up.... Dan
After staring at both photos for long enough I've almost started to believe that I understand the issue.
Because things are so cramped, the only place where thete is room for a conventional guardrail is on the straight side of the mainline frogs. All other movements rely on "self-guarded" frogs.
The way a self-guatded frog works is as follows: if the flange is riding hard up against the gauge face of the rail, then the outside edge of the wheel tread is pushed out over the field face of the rail. A little raised lip* in the casting on the field side of the rail will nudge the outside edge of the tread over, ensuring that the flange does not impact the point of the casting or, worse, go down the wrong side of the point and lead to a derailment.
However, this relies on the wheel being wide enough for the outside part of the wheel to impact that lip. If the distance from the gauge face of the rail to the raised lip is greater than the width of the wheel, then the wheel will never nudge against the lip and the wheel will not be steered correctly.
So when articles talk about the "wheel" or "wheel flange" being too narrow, they mean that the wheel itself is too narrow (where width is meausred parallel to the axle). When they talk about the "rail" being too "wide", they mean that the distance from the gauge face to the raised gauard is too wide. When they say that the problem only occurs for movements on the diverging route, this is correct - because the straight routes have proper guard rails opposite the frogs, and don't rely on self-guarding features of the casting.
Note that when I say "gauge face of the rail", I really mean "the face of the casting's flangeway that corresponds to the gauge face of the rail leading into the casting for the route being taken."
To complicate things a bit - you can see from the shiny wear marks in the photos that these are all flange-bearing frogs. (Probably to improve ride comfort, reduce noise, and tminimize impact loads on a very stiff direct-fixation track.) I don't think this fundamentally has anything to do with the underlying problem, but it might be related to why they have imposed a slow order on the STRAIGHT route (if indeed that is reported accurately). With a load-bearing flangeway, it might be that unusual wear or damage to the point is judged to introduce risk into the tracking of wheels traveling on the straight route, even if they are properly guarded? Or maybe there's something else at work.
And welding up the lip to make it thicker could well be effective at solving the problem - no different than building up a worn tread or point on any other frog - but not a cheap fix!
Or possibly I have missed the point completely.
* Footnote: the raised lip on a self-guarded frog seems to be the one piece of trackwork that doesn't seem to have an assigned name or slang term. At.least, I've never heard or seen one. Anyone else? If not perhaps we need to make one up....
Dan
Just for what it's worth, this subject came up in an AREMA on-line forum.as well. And someone who sounded (like they believe themselves to be) fairly knowledgeable about the situation did in fact describe the problem more or less as I had guessed: the wheel is too narrow to engage the self-guarding lip on the frog.
Former Car MaintainerPu'ulu moe kolohe...
.
BaltACD How do you pronounce cluster...k in Hawaiian?
How do you pronounce cluster...k in Hawaiian?
Pu'ulu moe kolohe...
Former Car MaintainerTrain the locals how to weld in manganese? https://www.staradvertiser.com/2021/10/22/hawaii-news/temporary-fix-planned-for-rails-too-narrow-wheels/?HSA=efb07aec5c6a8abc13b6194d037db7eb70f8a05f
Never too old to have a happy childhood!
Train the locals how to weld in manganese? https://www.staradvertiser.com/2021/10/22/hawaii-news/temporary-fix-planned-for-rails-too-narrow-wheels/?HSA=efb07aec5c6a8abc13b6194d037db7eb70f8a05f
Overmod What I deduce from the press conference a couple of days ago is that HART is proceeding with changing out the wheels, and that the frogs when welded will work with either kind of wheel (this 'future-proofs' the response) BUT no qualifying on-island welding firm appeared to have actually bid the job by a couple of days ago... leaving the procurement supposedly open. There is this picture that accompanied one of the paywalled stories: I am not sure precisely what it shows happening but it can't be good...
What I deduce from the press conference a couple of days ago is that HART is proceeding with changing out the wheels, and that the frogs when welded will work with either kind of wheel (this 'future-proofs' the response)
BUT no qualifying on-island welding firm appeared to have actually bid the job by a couple of days ago... leaving the procurement supposedly open.
There is this picture that accompanied one of the paywalled stories: I am not sure precisely what it shows happening but it can't be good...
Zugs: Suspect the reason for the custom trackwork are the confined spaces where there is enough length of real estate to keep the turnouts all in the same plane and in the same alignment for the speed they want. Transit is notorious for gnarly alignment issues and vertical curves that are a bozo-no-no in common carrier service. Transit, latecomer that it tends to be, has its corridor alinement determined by existing historic development. The dreaded yellow machines can't always reduce the neighborhood to a blank sheet of paper. (diningcar, PDN and I all have plenty of layout nightmare stories plus we all know how to cheat when we absolutely have to, our predecessors taught us well)
Space is rarely an issue but double crossovers may be used to minimize gaps in the third rail.
Ok, this is semi-related, but I have to ask:
What is with these transit systems and the need for crossovers with the big interlocked diamond thingies in the middle (the 2 combined switches crossign over each other). I can see if space is an issue, but many times it seems that 2 regular sets of crossover switches next to each other would work perfectly fine, without all the extra frogs and gurads and other associated metal bits?
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
dpeltier Overmod There is this picture that accompanied one of the paywalled stories: I am not sure precisely what it shows happening but it can't be good... Here's another photo from the same Star Advertiser article: After staring at both photos for long enough I've almost started to believe that I understand the issue. Because things are so cramped, the only place where thete is room for a conventional guardrail is on the straight side of the mainline frogs. All other movements rely on "self-guarded" frogs. The way a self-guatded frog works is as follows: if the flange is riding hard up against the gauge face of the rail, then the outside edge of the wheel tread is pushed out over the field face of the rail. A little raised lip* in the casting on the field side of the rail will nudge the outside edge of the tread over, ensuring that the flange does not impact the point of the casting or, worse, go down the wrong side of the point and lead to a derailment. However, this relies on the wheel being wide enough for the outside part of the wheel to impact that lip. If the distance from the gauge face of the rail to the raised lip is greater than the width of the wheel, then the wheel will never nudge against the lip and the wheel will not be steered correctly. So when articles talk about the "wheel" or "wheel flange" being too narrow, they mean that the wheel itself is too narrow (where width is meausred parallel to the axle). When they talk about the "rail" being too "wide", they mean that the distance from the gauge face to the raised gauard is too wide. When they say that the problem only occurs for movements on the diverging route, this is correct - because the straight routes have proper guard rails opposite the frogs, and don't rely on self-guarding features of the casting. Note that when I say "gauge face of the rail", I really mean "the face of the casting's flangeway that corresponds to the gauge face of the rail leading into the casting for the route being taken." To complicate things a bit - you can see from the shiny wear marks in the photos that these are all flange-bearing frogs. (Probably to improve ride comfort, reduce noise, and tminimize impact loads on a very stiff direct-fixation track.) I don't think this fundamentally has anything to do with the underlying problem, but it might be related to why they have imposed a slow order on the STRAIGHT route (if indeed that is reported accurately). With a load-bearing flangeway, it might be that unusual wear or damage to the point is judged to introduce risk into the tracking of wheels traveling on the straight route, even if they are properly guarded? Or maybe there's something else at work. And welding up the lip to make it thicker could well be effective at solving the problem - no different than building up a worn tread or point on any other frog - but not a cheap fix! Or possibly I have missed the point completely. * Footnote: the raised lip on a self-guarded frog seems to be the one piece of trackwork that doesn't seem to have an assigned name or slang term. At.least, I've never heard or seen one. Anyone else? If not perhaps we need to make one up.... Dan
Overmod There is this picture that accompanied one of the paywalled stories: I am not sure precisely what it shows happening but it can't be good...
Here's another photo from the same Star Advertiser article:
I follow and agree with your reasoning up to the point where you say, “To complicate things a bit”- where you begin talking about the flange bearing feature of the frogs. Studying the photo of the complete trackwork feature is helpful, but not 100%.
In looking at the close-up detail photo of the wheel on the frog, I see the apparent .5” gap between the outside surface (perpendicular to axle) of the wheel and the guiding side of the self-guarded frog flange. However, it seems that this gap is normal when the wheel is as far to the left as it can be, as is occurring; because the back-to-back side of the wheel flange is hard against the conventional frog-integrated guardrail on the left.
So if the wheel were to move to the right, it would close the gap between the outside surface of the wheel, and the guiding side of the self-guarded frog flange.
At the same time, the gage surface of the wheel flange will move up to very near to the gage face of the rail, where it has, at least the potential to pick the frog point and derail. Normally this would be prevented by a conventional guardrail guiding the wheelset by contacting the back-to-back side of the flange of the opposite wheel of the wheelset.
However, as you point out, there is no room for such a conventional guardrail in this overall trackwork arrangement. So, the solution is to rely on the raised flange of the self-guarding frog.
Therefore overall, I see no problem in the close-up photo of the wheel on the frog. In a very general sense, my hunch is that the problem is totally confined to the wheel-guardrail relationships in the crossing diamond. I would need to walk on site or see a more detailed photo or engineering drawing of this area to understand the problem.
As puzzles go, this is a masterpiece of two clever by half.
This was about the only thing that made any sense with 'wheels too thin' ... but it opens up the question about how, if they are replacing the wheels to 'correct width', the welded frogs would accommodate both the narrow and wider tread (at 55mph, as stated) presumably without picking.
Remember that the original indications that there were problems included cracking associated with excessive flange-bearing wear, which I took to be flanges going over the frogs in places they weren't intended to, and wearing off of some kind of silicone coating, which I naively associated with some kind of noise reduction rather than 'wear facing'. I think if someone with obsessive attention to detail 'used their power for good' we might be able to piece this together properly.
More clues from a HART power point presentation titled track issues
Switch slide plates
Cracking in the frogs
Wheel/rail interface
Speed through the double crossover in the tangent position
Additionally, a third party consultant TTCI has failed to release its investigative report on the matter for the third time... https://www.civilbeat.org/2021/10/hart-effort-to-hire-welders-to-fix-rail-tracks-falls-flat/
Additionally, the welding solicitation provides more clues http://hartdocs.honolulu.gov/docushare/dsweb/Get/Document-25220/Pre-Solicitation%20Notice_7-15-21.pdf
Overmod Euclid Who is recommending it? The person who said: What exactly is the welding supposed to accomplish...? In reading between the lines, I assume the point is to make the wheels 1/2" wider by building up the sides of the non-flange-side of the tread... and I guess this would save the cost of buying new wheels and replacing them on the axles. With the gigantic amount of welding to be done, what will it cost? It may be cheaper to just buy and replace new wheels. and In order to get welding production as high as needed, and to control weld quality control, it would seem preferable to use fixtured robotic welding to perfectly execute the weld buildup on each wheel.
Euclid Who is recommending it?
The person who said:
What exactly is the welding supposed to accomplish...? In reading between the lines, I assume the point is to make the wheels 1/2" wider by building up the sides of the non-flange-side of the tread...
and
I guess this would save the cost of buying new wheels and replacing them on the axles. With the gigantic amount of welding to be done, what will it cost? It may be cheaper to just buy and replace new wheels.
In order to get welding production as high as needed, and to control weld quality control, it would seem preferable to use fixtured robotic welding to perfectly execute the weld buildup on each wheel.
Yes I said those sentences that you quote, but you left out the part where I said I was reading between the lines to interpret what the plan was. This is necessary because I have yet to see a clearly presented reference to the actual problem.
No way was I “recommending” the procedure, as you say. I think it would be absurd to build up the wheels by welding.
I have not yet heard a technical explanation of what exactly this track/wheel problem consists of. Can you provide one that has been provided by this organization? I have found dozens of articles with explanations of the problem, but none that are clear enough to understand. I see those thoughtless explanations as likely to be a sign of the thinking that resulted in the problem.
All I need are some cross sections and detail views of the problem which is said to cause interference between frogs and wheels. I suspect they have not made drawings, but rather rely on their vendors to do the engineering.
EuclidWho is recommending it?
Overmod Note: never weld on a car wheel. Or even metalspray it. Gives me chills just thinking someone would glibly recommend it.
Note: never weld on a car wheel.
Or even metalspray it.
Gives me chills just thinking someone would glibly recommend it.
Who is recommending it?
EuclidWhat exactly is the welding supposed to accomplish as a fix to this "too wide, too narrow" dilemma?
Our community is FREE to join. To participate you must either login or register for an account.