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Superliner Stability

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Superliner Stability
Posted by PJS1 on Tuesday, July 26, 2022 3:06 PM
What is the likelihood of Superliner cars rolling over in a derailment compared to single level cars? 
 
Do the Superliner cars have any features that reduce the probability of a rollover? 

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Posted by Enzoamps on Tuesday, July 26, 2022 10:34 PM

I don't know, but it would seem the important thing is center of gravity rather than how tall they are.  And I don't know that about either.

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Posted by BEAUSABRE on Wednesday, July 27, 2022 7:21 AM

I'm sure there is AAR, FRA or both standards on CG and propensity to rolle CFR :: 49 CFR Part 238 -- Passenger Equipment Safety Standards

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Posted by Overmod on Wednesday, July 27, 2022 11:16 AM

Oh, for heaven's sake, of course they are more prone to roll over in a derailment, and equally of course to do so very quickly if they derail sufficiently to put wheels over the edge of the ballast prism.

If you look at the overturning moment arm at the bolster, and compare it with the roll center, you can easily see the instability just for slight lateral tilt, let alone accelerated roll.  To me the problem is exacerbated by the design of the Waggon Union low-unsprung-mass trucks, but both they and the GSC trucks just don't have serious roll control for more than small perturbations.

I have not studied the extent to which Superliners 'going over' will torque the coupling to accelerate tipover.  It shouldn't be difficult to calculate.  I thought years ago that 'high-level' cars ought to have rotary couplers to prevent that sort of cause of accelerated overturning.

There really isn't much that can be done to make the situation 'safer'.  As with the generations of lightweight car that went before, something can be done about the windows breaking out and projecting people far enough to be dragged or 'rolled over on'.  The issue then becomes what happens if those windows then have to be removed or 'opened' to get people out...

You could have some kind of 'landing gear' that projects out to slow down the roll.  Or large air bags that deploy sequentially to help hold the car upright or at least cushion the rollover.  The reason these are Not Particularly Good Ideas is that all sorts of fun ensues if they deploy unintentionally.

You might get somewhere by adopting the Pendulum Car style of 'tower' up to the floor of the upper level, which essentially 'hangs' all the lower floor structure to generate restoring force, or the Cripe-style pendulum suspension from the roof (with the portal in the frame moving relatively slightly on the upper level, where that most matters) -- reinforcing the car structure accordingly.  If you combined this with the sort of exaggerated OSH construction in the last orders of New Haven cars, you'd get maximum effective bolster plank width; and you could fire a pyrotechnic charge and foam into the air bags on the car to give some active force early in a tipover, although again I think the cure would be worse than the disease.

charlie hebdo will agitate for better CEM in the passenger areas, and I'll pre-emptively agree with him that that's the best, most easily implemented, and perhaps overall the most effective method of preventing injuries when, not if, the things tip over.

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Posted by charlie hebdo on Wednesday, July 27, 2022 1:40 PM

Overmod
charlie hebdo will agitate for better CEM in the passenger areas,

Jargon, Jargon.  And purple prose. 

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Posted by PJS1 on Wednesday, July 27, 2022 8:45 PM

Overmod,

I understand top heavy vehicles are more prone to roll over in a crash. 
 
The purpose of my question(s) was to gain some insights into what controls, if any, the designers of the Superliners baked into the cars to reduce the probability of rollovers or, if they happen, the controls designed to mitigate the impact.
 
Your insights, which appear to be based on sound engineering principles, are very helpful.  I appreciate them.  

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Posted by Lithonia Operator on Wednesday, July 27, 2022 9:07 PM

What is CEM?

Still in training.


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Posted by SD70Dude on Thursday, July 28, 2022 2:04 AM

Lithonia Operator

What is CEM?

Collision/Crash Energy Management

Greetings from Alberta

-an Articulate Malcontent

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Posted by Lithonia Operator on Thursday, July 28, 2022 7:07 AM

Thanks, Dude.

Still in training.


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Posted by azrail on Thursday, July 28, 2022 10:56 AM

The Superliners were basically clones of Santa Fe's Hi-Levels. But they were made of less durable metals than the Santa Fe cars-they crush easier.

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Posted by blue streak 1 on Thursday, July 28, 2022 11:27 PM

azrail

The Superliners were basically clones of Santa Fe's Hi-Levels. But they were made of less durable metals than the Santa Fe cars-they crush easier.

 

 
My experience with Pacific Parlor cars was they were slightly lower.  Know that the 2nd floor of Parlor was lower.  Ceossing from Parlor to SL almost stumbled on the higher SL 
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Posted by Overmod on Friday, July 29, 2022 8:20 AM

charlie hebdo
Overmod
charlie hebdo will agitate for better CEM in the passenger areas,

Just poor semantics on my part.  I wasn't being pre-emptively critical -- I was actually inviting you to comment on CEM, as I think you are familiar with the current state-of-the-art as applied to European equipment.
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Posted by charlie hebdo on Friday, July 29, 2022 10:15 AM

I am not an engineer. That said, I think it is difficult to retrofit older generation Amtrak equipment with lateral or longitudinal CEM passive measures.

I'm wondering how the superliner center of gravity compares with double deck equipment in Europe or Asia?

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Posted by Overmod on Friday, July 29, 2022 11:21 AM

charlie hebdo
I think it is difficult to retrofit older generation Amtrak equipment with lateral or longitudinal CEM passive measures.

I would agree. and I'd add that those measures that actually could 'fit' might be of limited or even dubious value in an actual accident.

One problem I see coming is that, with these fairly high-profile derailments dumping consists on their side, that lawyers will try to establish that the basic Superliner design is fundamentally unsafe.  If they do, Amtrak may have no choice but to implement some kind of positive safety attempt... no matter how parlous in actual situations.

I'm wondering how the Superliner center of gravity compares with double deck equipment in Europe or Asia?

It was my understanding that most of the European and Asian equipment had a more restricted loading gauge, and in some cases the upper floor was curved for tunnel clearance reducing the moment arm for a given roll center.  True 'double-deck' equipment would also have increased mass low down in the carbody compared with high-level American equipment, I think.

Having said that, the fastest railroad train in the world at this point is a French bi-level, so I think there is clearly going to be some solution that would make a high-level HSR or 125mph service a possibility.  It is certainly an option for non-commodity-corridor adaptation of PRIIA, which I think is the logical follow-on for Superliners (despite the initial Siemens 'Amfleet replacements') when it comes time... fairly soon, I think, 2024?... to start replacing them.  Those shells can be carefully designed to minimize tipover, and be given adequate glazing and internal-impact management as well as better passenger restraint methods.

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Posted by charlie hebdo on Friday, July 29, 2022 11:44 AM

Perhaps more suitable for Amtrak is the DB IC2

https://images.app.goo.gl/Gj475E5nEdyVz6QX9

 

 

 

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Posted by BEAUSABRE on Friday, July 29, 2022 1:22 PM

Overmod
that lawyers will try to establish that the basic Superliner design is fundamentally unsafe. 

If they do, it will be devatating to ATK - 428 of their 1408 cars are Superliners (30 percent), another 88 are state owned Bi-Levels, not included in the 1408, but would probably be tarred with the same brush. Amtrak, to protect itself, would have remove the Superliners from service both from a PR standpoint (How many people would be patrons of an airline found to be flying aircraft of "fundamentally unsound" design) and legal standpoint ("You knew the Superliners were unsafe, but continued to operate them, Mr Amtrak president"). This wouldn't be something that Beech Grove could fix with a few tweaks - it's inherent in the design, as determined in a court of law. As far as replacements go, they would take years to build and Amtrak doesn't have the money, anyway (maybe siphon off some of the infrastructure dollars, but then someone's pet project dies). So ATK can forget about expanding the routes it offers and either cut the size of trains or drop the route all together. Better hope Amtrak (and the builders or their corporate descendents and the FRA for allowing them to run) have some top notch lawyers...

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Posted by BEAUSABRE on Friday, July 29, 2022 2:46 PM

About the only quick fixes I can think of are to install seatbelts and seat back airbags and enforce the rules of remaining buckled up and no unnecessary walking about (potty breaks only). Refreshments will be delivered to your seat when a member of the crew passes by with the cart (you preselect meals either with your reservations or from a list the staff member takes down - just like an airliner. You buy drinks off the cart.The old dining car would become a kitchen-coach). Which would be bandaids (and may not be either practical or pass legal liability muster) and also destroy some of the ambiance ATK is trying to sell. "You can get up and walk around"

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Posted by ORNHOO on Friday, July 29, 2022 3:35 PM

I, for one, have always found it unfortunate that Isambard Kingdom Brunel did not have a more lasting influence on the subject of railroad gauge. A wider stance on the rails would go far to mitigate the effect of a higher center of gravity.

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Posted by charlie hebdo on Friday, July 29, 2022 7:04 PM

Rather more expensive than simply buying better equipment, doncha think?

 

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Posted by Overmod on Sunday, July 31, 2022 6:32 AM

ORNHOO
I, for one, have always found it unfortunate that Isambard Kingdom Brunel did not have a more lasting influence on the subject of railroad gauge. A wider stance on the rails would go far to mitigate the effect of a higher center of gravity.

Except that the same principle was applied to much of the early permanent-way narrow (standard) gauge construction in Britain, and see where that got them?

Had even the 6' gauge persisted in the United States, you would have seen its loading gage brought out to the stable maximum, as in the 3m Breitspurbahn later.  One of the arguments about doing this with Brunel's even wider gauge is that the axles start to become fairly heavy without intermediate support when you get into 'cost-effective' loading.

Now, it might have been interesting to see a world in which overhead clearances were restricted to, say, New York Central levels, but on 6' or 7-and-a-fraction gauge out to stable limits.  That would have allowed relatively wide cabins with 'steamboat' ceiling height; staterooms on either side of a central aisle, etc.  But the American love of property tax would likely have ruined this before it could be extensively built out.

There have been periodic attempts to bring the idea back either for stability or convenience.  I was impressed when young by the Trains article on the case for the double-track train, and by the RRollway that operated on three-rail broad gauge to accommodate then-enormous American cars driven on and off transversely.  (Note that I do not mention explicitly a certain mid-Seventies jiggle-show Love Boat on wheels...)

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Posted by Overmod on Sunday, July 31, 2022 6:45 AM

If I remember correctly, Siemens offered this or a very similar double-deck shell as one option for the Amfleet replacement, and it was 'not proceeded with' in favor of the same company's single-level offering.

In part this is because the low-level 'possum belly' construction requires stairs or ramps compliant with the ADA for use with high-level platforms.  This is much less of a concern with much of the LD service; in fact low-floor entrances in Superliners are a boarding advantage for many... if there is some provision to get the disabled to the upper level.  That would be a terrible space-waster and perhaps integrity compromiser if implemented in each car (presumably as a wheelchair-and-attendant sized electric elevator).

If you put sleeper accommodation on the lower level of an IC2 you're going exactly counter to the ideas of high-level cars in the first place; if you put them on the upper level the space becomes disturbingly cramped for most people familiar with legacy sleeper accommodation unless the shell is redesigned taller and wider.  (Disclaimer:  I am a great fan of Corb's 'machine a habiter' use of small, snug sleeping environments.  I like tiny houses, 'capsule hotels', and some of those European and Asian hostel-style multilevel bunks for 'assisted coach travel', so reminiscent of open sections.)  While the upper deck of an IC2 is certainly crowded by Superliner standards, you can get at least the effect of roomettes in there -- but I suspect it will be a hard sell to charge current Amtrak prices for the resulting accommodation unless there are truly wonderful amenities... something Amtrak is poor at either supplying or maintaining.

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Posted by BEAUSABRE on Sunday, July 31, 2022 8:18 AM

Overmod
 I am a great fan of Corb's 'machine a habiter' use of small, snug sleeping environments.  I like tiny houses, 'capsule hotels', and some of those European and Asian hostel-style multilevel bunks for 'assisted coach travel', so reminiscent of open sections

We're Americans, we expect and demand bigger. There have been some reviews on line by millenials and Gen Z'ers and they all found the sleeper accomodations ingenious but cramped - to some reviewers terribly so. 

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Posted by charlie hebdo on Sunday, July 31, 2022 1:10 PM

OM: I was thinking more of the IC2 design for the coach portion of LD trains and single level for sleeper accomodations. As has been pointed out on here numerous times, most LD train passengers are riding to/from and between  intermediate stops.  So it is likely they are not overnighters requiring berths. 

As to smaller berths: I'm 6'2" and retired. I have no problem with berths on European overnight trains and when I was a bit younger, the 4-bunk couchettes we're fine. Many Europeans are large, BTW.

 

 

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Posted by Overmod on Monday, August 1, 2022 8:05 AM

In my not-so-humble opinion: I would thoroughly agree with IC2-style coaches for LD (with the 'extra space' used for a wide range of potential amenities to make the experience better) but I would retain high-level full sleepers if possible, and use the upper level of the IC2 equipment for the 'gangways' to the sleepers.  With some care in designing the intercar transitions, this might allow in-train use of Superliners with newer equipment that has different vestibule height.

One thing the IC2 equipment would facilitate would be the use of dome-style 'fenestration' on the upper deck -- the existing cars go a long way toward it -- and repurpose the lower one as 'sleeping chairs' or hostel-style bunking.  This solves the issue with coach seat tracking and, I think, provides an immediate path to multiple types of inexpensive ways to endure, or should I say enjoy, what may be multiple-day trips on LD services.  

You will get no argument from me regarding sleeping comfort: my concern was that 'Murican' sleeper passengers might not understand or appreciate the smaller and tighter accommodation size.  I admit I was thinking of the existing IC2 envelope (I think it conforms to a UIC plate size) with sleeping accommodations on that upper level.

You'd probably want the equivalent of those bus hoverchair mechanisms in seats mounted in possum-belly -- I think we learned valuable lessons with all those lightweight and 'tubular' equipment in the '50s.

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Posted by charlie hebdo on Monday, August 1, 2022 9:13 AM

Overmod
You'd probably want the equivalent of those bus hoverchair mechanisms in seats mounted in possum-belly -- I think we learned valuable lessons with all those lightweight and 'tubular' equipment in the '50s.

 

Perhaps necessary since much American trackage is in poor condition compared to track on the DB.

Superliners are top-heavy and unsafe for speeds over ~50mph given rough trackage and hazardous crossings on most lines outside of a few corridors.

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Posted by PJS1 on Monday, August 1, 2022 8:35 PM

Since we are on the topic of Superline cars, let me pose another question.

According to several news sources, Union Pacific and Norfolk Southern are rebuilding some of their older locomatives.  The rebuilds, according to the articles, could extend the life of the locomotives up to 20 years.

Instead of buying new cars for the Superliner equipped long-distance trains, would it be technically and economically feasible to rebuild the Superliner cars?  If so, how long would the rebuilds be expected to last? 

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Posted by blue streak 1 on Monday, August 1, 2022 11:47 PM

PJS1

trains, would it be technically and economically feasible to rebuild the Superline cars?  If so, how long would the rebuilds be expected to last? 

 

 
The question first needs to ask how quickly can they be rebuilt?  Amtrak as I understand has a lot of vacancies at Beech Grove they have not been able to fill.
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Posted by BEAUSABRE on Tuesday, August 2, 2022 12:12 AM

charlie hebdo
Superliners are top-heavy and unsafe for speeds over ~50mph given rough trackage and hazardous crossings on most lines outside of a few corridors.

OK, rather than make an assertion, try providing references to back it up

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Posted by charlie hebdo on Tuesday, August 2, 2022 11:20 AM

BEAUSABRE

 

 
charlie hebdo
Superliners are top-heavy and unsafe for speeds over ~50mph given rough trackage and hazardous crossings on most lines outside of a few corridors.

 

OK, rather than make an assertion, try providing references to back it up

 

 

Most postings on here are assertions or opinions. Citations only are needed when a third party is a source. 

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Posted by charlie hebdo on Tuesday, August 2, 2022 11:21 AM

BEAUSABRE

 

 
Overmod
 I am a great fan of Corb's 'machine a habiter' use of small, snug sleeping environments.  I like tiny houses, 'capsule hotels', and some of those European and Asian hostel-style multilevel bunks for 'assisted coach travel', so reminiscent of open sections

 

We're Americans, we expect and demand bigger. There have been some reviews on line by millenials and Gen Z'ers and they all found the sleeper accomodations ingenious but cramped - to some reviewers terribly so. 

 

 

You refer to articles by third parties. Citations?

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