Havey: Sorry I did not list whole sequence. Here it is.
. http://www.amtrak.com/servlet/ContentServer/Page/1241245669222/1237608345018
Edit:: This is AMTRAK reports. Go half way down page to Comprehensive Business Plans: Click on Fleet Strategy Plan
The study that states that "wide body" and "truck instability" at higher speeds caught my attention about the tilting problem.
The study also suggests that new-generation trains can achieve 180-200 mph on existing, non-improved infrastructure.
I did quite enjoy and totally accept the idea that intermediate catenary supports could support Acela at 150 mph south of New York as an intermediary measure.
This paper needs to be taken with a grain of salt, and I'm rather leery of the lack of sources in the paper.
Got it. Thank you very much.
Quick comments:
blue streak 1Havey: Sorry I did not list whole sequence. Here it is. . http://www.amtrak.com/servlet/ContentServer/Page/1241245669222/1237608345018 Edit:: This is AMTRAK reports. Go half way down page to Comprehensive Business Plans: Click on Fleet Strategy Plan
If "wide body," "truck instability," and "achieve 180-200 mph on existing...infrastructure" were in the Amtrak Fleet Strategic Plan, I missed it.
Harvey
aegrotatio The study that states that "wide body" and "truck instability" at higher speeds caught my attention about the tilting problem.The study also suggests that new-generation trains can achieve 180-200 mph on existing, non-improved infrastructure.I did quite enjoy and totally accept the idea that intermediate catenary supports could support Acela at 150 mph south of New York as an intermediary measure. This paper needs to be taken with a grain of salt, and I'm rather leery of the lack of sources in the paper.
aegrotatioI did quite enjoy and totally accept the idea that intermediate catenary supports could support Acela at 150 mph south of New York as an intermediary measure
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
That's a little different than my take that it would be difficult to support both new and old catenary from an existing pole or bridge in addition to the issue of distance between supports.
oltmanndaegrotatioI did quite enjoy and totally accept the idea that intermediate catenary supports could support Acela at 150 mph south of New York as an intermediary measureI understood that to mean that the construction of constant tension catenary on the south end of the corridor would allow reuse of the existing catenary poles by adding new ones in between. It's not a half-way step, really. Just a construction detail.
The way I understand the CAT problem is that the current variable tension PRR cat will work up to 125 -135 MPH (depending on temperature). Above that speed the CAT bounces up and down at various rates causing the PAN not to follow the wire and the contact between the two makes and breaks. By adding a horizontal support 1/2 way between the present PRR horizontals ( perpendicular to track) the variable tension cat will not bounce at speeds up to 150 MPH. Above that speed constant tension is needed. The current PRR spacing is too far apart for constant tension and the intermediate horizontals will fix that problem as well. So the intermediate horizontals will be needed any way for constant tension. I have been trying to find out what maximum spacing can be used for constant tension but so far have had no luck.
HarveyK400 That's a little different than my take that it would be difficult to support both new and old catenary from an existing pole or bridge in addition to the issue of distance between supports. Harvey oltmanndaegrotatioI did quite enjoy and totally accept the idea that intermediate catenary supports could support Acela at 150 mph south of New York as an intermediary measureI understood that to mean that the construction of constant tension catenary on the south end of the corridor would allow reuse of the existing catenary poles by adding new ones in between. It's not a half-way step, really. Just a construction detail.
blue streak 1I have been trying to find out what maximum spacing can be used for constant tension but so far have had no luck.
I think the Siemens website might have that info.
C&NW, CA&E, MILW, CGW and IC fan
Contact, arcing, is a problem; but I think worse issues arise at extreme temperatures. Wires get pulled down by the train in extreme weather (and rip off the pantograph) at conventional speeds. The force and harmonics of the pan may be too much for more brittle and stretched copper wire at low temperatures; and the expansion and sagging of the contact wire may be prone to whipping around the pan in high temperatures. The hot weather sagging between supports, like waves, also produce a bounce at the supports.
blue streak 1The way I understand the CAT problem is that the current variable tension PRR cat will work up to 125 -135 MPH (depending on temperature). Above that speed the CAT bounces up and down at various rates causing the PAN not to follow the wire and the contact between the two makes and breaks. By adding a horizontal support 1/2 way between the present PRR horizontals ( perpendicular to track) the variable tension cat will not bounce at speeds up to 150 MPH. Above that speed constant tension is needed. The current PRR spacing is too far apart for constant tension and the intermediate horizontals will fix that problem as well. So the intermediate horizontals will be needed any way for constant tension. I have been trying to find out what maximum spacing can be used for constant tension but so far have had no luck. HarveyK400 That's a little different than my take that it would be difficult to support both new and old catenary from an existing pole or bridge in addition to the issue of distance between supports. Harvey oltmanndaegrotatioI did quite enjoy and totally accept the idea that intermediate catenary supports could support Acela at 150 mph south of New York as an intermediary measureI understood that to mean that the construction of constant tension catenary on the south end of the corridor would allow reuse of the existing catenary poles by adding new ones in between. It's not a half-way step, really. Just a construction detail.
HarveyK400Contact, arcing, is a problem; but I think worse issues arise at extreme temperatures. Wires get pulled down by the train in extreme weather (and rip off the pantograph) at conventional speeds. The force and harmonics of the pan may be too much for more brittle and stretched copper wire at low temperatures; and the expansion and sagging of the contact wire may be prone to whipping around the pan in high temperatures. The hot weather sagging between supports, like waves, also produce a bounce at the supports.
Harvey: Absolutely correct. The only thing is pure copper wire is no longer used for new Eurpean HSR but an alloy and maybebe even a center core of different lighter weight metal depending on the temperature extremes at any location. One item is the lighter the CAT is the better the interaction of the PAN and the wire by reducing harmonics Of course current carrying capacity has to be considered therefor the trend towards 25Kv CAT to reduce weight.
blue streak 1The way I understand the CAT problem is that the current variable tension PRR cat will work up to 125 -135 MPH (depending on temperature). Above that speed the CAT bounces up and down at various rates causing the PAN not to follow the wire and the contact between the two makes and breaks. By adding a horizontal support 1/2 way between the present PRR horizontals ( perpendicular to track) the variable tension cat will not bounce at speeds up to 150 MPH. Above that speed constant tension is needed. The current PRR spacing is too far apart for constant tension and the intermediate horizontals will fix that problem as well. So the intermediate horizontals will be needed any way for constant tension. I have been trying to find out what maximum spacing can be used for constant tension but so far have had no luck.
HarveyK400If "wide body," "truck instability," and "achieve 180-200 mph on existing...infrastructure" were in the Amtrak Fleet Strategic Plan, I missed it.
No need to be testy. I was talking about the one labelled "Interim Assessment of Achieving Improved Trip Times on the Northeast Corridor - PRIIA Section 212 (d)"
It's great but lacks sources. I'm not sure the link will work. It's the first one in the section entitled "PRIIA Submissions and Reports."
Speaking of HSR, anyone else hearing the Siemens commercials on the radio about American High-Speed Rail?
Don't ask me why; but I finally found the citation after 3 days.
The general blame for not achieving speeds greater than 135 mph on curves because of body width and instability of truck and suspension systems is misleading.
As for truck and suspension instability, it was stated by someone that 6" cant was allowed on the NEC between New York and Washington (DC). However, the report coincides with only 4" cant for the predominant number of 1-degree curves. The Acela tilt range is at it's limit of 8 degrees, equivalent to 8.56" cant deficiency with 4" cant, where 8.35" cant deficiency would be reached at 135 mph. 8 degree of tilt would be surpassed at 136 mph. Maybe "bottoming out" is the cause for the instability? Furthermore, there is only 0.21" allowance for deviation(?) in cross-alignment notwithstanding the wheel rail dynamic impact at 135 mph that may further reduce the allowable surface deviation. Near-perfect track is required; and may only be achievable with slab construction. The more practical solution would be to limit Acela to a more forgiving 130 mph that would be less disturbing to passengers.
As long as freight traffic continues to use the NEC, even if just to serve customers, high center of gravity (up to 8'4") cars become increasingly unstable due to limited spring travel as cant increases.
The report seems to lump both the Washington and Boston legs together; but the body width and inability to achieve full tilting seems from other sources to be an infrastructure issue only on the Boston leg. Even so, many curves on the Boston section are generally sharper, 1.5 degree; and would restrict Acela speed to a nominal 105 mph with 4" cant notwithstanding the closer track centers.
A conventional train with outside swing hangers or bolster springs with an FRA waiver for 5" cant deficiency would be allowed a nominal 90 mph allowing for some surface deviation. Sound familiar and consistent with the current speed limits? My guess is that is the limit in part to maintain clearance between trains on adjacent tracks. Maybe an 8" narrower Acela would have allowed higher speeds; but it's possible that narrower interior space was an over-riding consideration. In any event, speeds would not be high enough to require grade separation; and such grade separation would have been highly disruptive for coastal development along the route.
180-200 mph capability is assumed although not explicitly for any particular segment of the NEC; while speeds above 150+ mph are assumed generally achievable for the NEC with new tilting equipment. For 1.5-degree curves on the Boston leg, that would take over 18.88", 18.48-degrees, of tilt. 19 degrees of tilt would allow 180 mph for 1-degree curves. The problem is that twice the currently available technology.
I only had a fleeting glimpse of the Siemens commercial - wasn't really paying attention.
Thanks for the comments.
I would like to know what that report means by "new generation equipment." It seems to mean by "equipment" is the train itself and not track/catenary.
That would be my interpretation as well.
aegrotatio Thanks for the comments.I would like to know what that report means by "new generation equipment." It seems to mean by "equipment" is the train itself and not track/catenary.
HarveyK400 many curves on the Boston section are generally sharper, 1.5 degree; and would restrict Acela speed to a nominal 105 mph with 4" cant notwithstanding the closer track centers. A conventional train with outside swing hangers or bolster springs with an FRA waiver for 5" cant deficiency would be allowed a nominal 90 mph
A conventional train with outside swing hangers or bolster springs with an FRA waiver for 5" cant deficiency would be allowed a nominal 90 mph
http://maps.google.com/?ie=UTF8&ll=41.907036,-71.310925&spn=0.009646,0.019248&t=h&z=16
HarveyK400 the report coincides with only 4" cant for the predominant number of 1-degree curves. The Acela tilt range is at it's limit of 8 degrees, equivalent to 8.56" cant deficiency with 4" cant,
The cant only needs to be, and probably is, 4" along with the 5" cant deficiency for a nominal 90 mph limit. I suspect the 100 mph curve is slightly broader, perhaps 1.25-degree. I'm guessing the 135 mph limit on the south end is pushing 8-degrees tilt with 4" cant; but I tried to explain my reasoning on that. The Amtrak report, while generally descriptive, is not accurately written which results in some confusion.
timzHarveyK400 many curves on the Boston section are generally sharper, 1.5 degree; and would restrict Acela speed to a nominal 105 mph with 4" cant notwithstanding the closer track centers. A conventional train with outside swing hangers or bolster springs with an FRA waiver for 5" cant deficiency would be allowed a nominal 90 mph Amfleet trains are allowed 90 mph around several 1.5-degree curves, supposedly with 6-inch cant; they're allowed 100 around the 1.5-degree curve east of Providence (where the RR swings onto the original alignment-- MP 205 or some such thing). http://maps.google.com/?ie=UTF8&ll=41.907036,-71.310925&spn=0.009646,0.019248&t=h&z=16 HarveyK400 the report coincides with only 4" cant for the predominant number of 1-degree curves. The Acela tilt range is at it's limit of 8 degrees, equivalent to 8.56" cant deficiency with 4" cant, Just to clarify-- Acela never uses 8 degrees of tilt, does it?
Cant on a 1.5-deg curve would need to be 4 inches for an Amfleet train at 90 mph, assuming 5 inches cant deficiency-- which only Amfleet is allowed, right? The Florida trains would only be allowed 3 inches? I'll check, but as I recall the long-distance trains are allowed 90 on the same 1.5-deg curves.
FWIW, the charts do show 6 inches cant on lots of curves. Acela does 130 around alleged 1-deg curves with 5.5-6 inches cant, and as I recall they don't try to tilt enough to balance all the cant deficiency-- 70%, maybe? So no 8-degree tilting.
All this talk of about tilt seems to be not attacking the core problems. An analysis of the PRII gave a close idea of the order of improvements. Probably the NYP - PHL segment would give most bang for the buck not counting the number of passengers compared to the other segments. The cost of upgrading the "S" curve at Elizabeth and curves at Lincoln (Edison) Croyden (?),Torresdale, & Frankfort will require about 500M. Signals 50M and Constant Tension 250M This would give a fast track except Trenton station Newark - PHL and will save about 8 - 10 Minutes. and another 5 minutes for other improvements.
Higher speeds are not possible until the CAT is fixed and the full abilitys of the Acela type vehicles is used and not being limited by present 100 MPH curves. That would make full use of tilt on both Acela and newer equipment.
Will not under an hour time NYP - PHL cause the public to sit up and take notice? An average of over 90 MPH. These improvements will also help NJ Transit and Septa with their elec motor hauled trains.
The track work in De, Md, and DC looks to cost much more due to the three Md bridges and the B&P tunnels.+ The need to add tracks to the present 2 & 3 track setup.(over $3B)
It really can be a hard decision to concentrate on one segment over another.
Sure it's nice to ease the few worst curves; but they represent a very small amount of total route mileage, even taking into account braking and speed recovery distances. Even if, as some say, 6" cant and 8" tilt is allowed, that only permits 140 mph. Maybe some new-generation Acela can provide more tilt; but I don't see money for slab track and wider track centers. There is a long way to go to get to 180 mph on the existing alighnment; and there isn't much time to develop such a tilt system and tosolve infrastructure conflicts if production on cars is to begin in 3-4 years.
Another confounding piece is that, despite acknowledging the capacity issue, Amtrak seems poised to continue on the same single-level path. A 30% increase in capacity with bi-levels, especially for both Regional and Acela peak period trains, would offer some relief while Hudson River tunnels can be built and permit double the number of trains.
blue streak 1All this talk of about tilt seems to be not attacking the core problems. An analysis of the PRII gave a close idea of the order of improvements. Probably the NYP - PHL segment would give most bang for the buck not counting the number of passengers compared to the other segments. The cost of upgrading the "S" curve at Elizabeth and curves at Lincoln (Edison) Croyden (?),Torresdale, & Frankfort will require about 500M. Signals 50M and Constant Tension 250M This would give a fast track except Trenton station Newark - PHL and will save about 8 - 10 Minutes. and another 5 minutes for other improvements. Higher speeds are not possible until the CAT is fixed and the full abilitys of the Acela type vehicles is used and not being limited by present 100 MPH curves. That would make full use of tilt on both Acela and newer equipment. Will not under an hour time NYP - PHL cause the public to sit up and take notice? An average of over 90 MPH. These improvements will also help NJ Transit and Septa with their elec motor hauled trains. The track work in De, Md, and DC looks to cost much more due to the three Md bridges and the B&P tunnels.+ The need to add tracks to the present 2 & 3 track setup.(over $3B) It really can be a hard decision to concentrate on one segment over another.
Harvey my point is that the Newark - Phl can become almost straight track with very gentle curves except for the section inside Philidelphia city. The "S" curve at Elizabeth is almost the same direction approaching and leaving, (about 4 -5 degrees) The curve at Lincoln (edison) is a left southbound curve of 10 - 15 degrees around edison yard that is mostly not used for the closed ford plant. This should give a long (34 mile) run for true HSR. (170+)
The straightening of Trenton - PHL will help although I forsee many problems to changing the track from Frankford yard Jct thru Shore and the flyovers needed at 16th st/north Philadelphia jct. That is where the tilt is very important.
Off subject of this post the need for low center of gravity locos and motors to haul tilt trains is not IMHO being pushed enough. Are the European operators pulling tilt trains using any thing along that line?
blue streak 1Off subject of this post the need for low center of gravity locos and motors to haul tilt trains is not IMHO being pushed enough. Are the European operators pulling tilt trains using any thing along that line?
European and Japanese tilting trains mostly use distributed power. If there are separate power units front and rear, they are matching. Again, the wiki article is quite comprehensive with pics:
I also suggest going to the Talgo website. The high-speed Talgos used in Spain have low profile (and center of gravity) integrated power cars at both ends of the train. These are not compatible with high level platforms.
Japanese and the Fiat (Siemens?) tilt trains may have distributed powered coaches with a lower center of gravity and are designed for high level platforms.
schlimmblue streak 1Off subject of this post the need for low center of gravity locos and motors to haul tilt trains is not IMHO being pushed enough. Are the European operators pulling tilt trains using any thing along that line? European and Japanese tilting trains mostly use distributed power. If there are separate power units front and rear, they are matching. Again, the wiki article is quite comprehensive with pics:http://en.wikipedia.org/wiki/Tilting_train
Harvey: I believe the Fiat and Siemens tilting trains are similar but not the same design.
I was sloppy - the Fiat Pendolino successors are now built by Alstom, not Siemens
schlimm Harvey: I believe the Fiat and Siemens tilting trains are similar but not the same design.
I notice that inner city buses, through buses, and tour buses tilt the wrong way quite a bit on almost any curve. As far as I know, the bus passengers don't complain.
I don't think tilting helps to reduce wheel and track wear as superelevation does. Therefore, my opinion is that tilting introduces additional mechanical parts that we can well do without. We should focus instead on getting the best compromise for superelevation, which will balance the train loads at one selected speed and minimize wear on all the equipment.
Isn't there a physical limit to the amount of super-elevation that can be employed on lines jointly used by passenger and frieght, especially if the train is not moving?
Hays
BNSFwatcherIsn't there a physical limit to the amount of super-elevation that can be employed on lines jointly used by passenger and frieght, especially if the train is not moving? Hays
Bill: There must be but oltmann would know. I remember running on some indoor, wooden tracks that had very tight, but banked turns. Running was great but if you stopped you had to be careful or you would feel like falling over.
Bus passengers, at least this one, are too busy gripping the arm rest and praying the bus doesn't tip. The OTR cruisers are up so high it's a wonder they don't roll over more often; and a transit bus full of standees is a lot of shifting weight on a hard corner.
For what it's worth, I was dozing off in a Lakeshore bedroom when we it hit a low joint (grade crossing?) at 110 mph between Albany and Schenectady, bottomed out on the springs, and seemingly rode on four wheels. That woke me up and broke a sweat. I thought it better to lie to my wife.
In the interest of fair disclosure, I've had many white-knuckle moments driving and flying too.
The compromises for superelevation (cant) have been made. You are correct in that tilt does not reduce wheel and track wear; but tilt allows faster comfortable passenger speeds where cant (superelevation) already is at the host railroad's limit for freight service. As posted in these forums, NS uses a higher cant for more competitive freight speeds on the former Southern, and of course the NEC uses more cant and accepts the cost consequences with mixed traffic for faster passenger trains.
A vehicle will tip roughly the equivalent of the overbalance in addition to the cant relative to spring travel and height of the center of gravity above top of rail.
First, 286,000 lb cars are pretty much on the edge of metallurgy; so high overbalance for increased passenger speed can shift a significant proportion of freight car weight to the low rail. The weight transfer is aggravated by cars with a higher center of gravity of 90-100 inches (compared to a passenger car's roughly 60 inches). This results in plastic deformation and fissures in the railhead that are a defect that must be addressed with restrictions until replaced and reduces rail life much faster than surface wear. Comparable damage is done to the wheel tread. In overbalance, the wheel flange will be in contact with the inner rail head and wear both to the extent that gauge limits are exceeded.
The second problem is that freight cars had comparatively short spring travel, most four inches or less (I'm not clear on this - best case it's for a loaded car). I'm not familiar with today's status; but spring travel was trending upward. Cant over 3" really affects the softness of the ride with even Class IV and Class V track; so higher cant would be problematic at lower speeds.
Third, high cant and sharper curves leave a train more susceptible to a bow-sting derailment where cars are pulled off the tracks to the inside of the curve.
If my approximation is close, a car with a 90" high c/g and 4" spring travel wouldn't tip over standing still without almost 14" cant; so train dynamics and rail degradation would be more limiting.
I may have missed something; but these are my understanding of the issues.
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