I suppose there may be a breakdown of intercity travel by trip purpose somewhere. I just wonder if business travel is the backbone for intercity. Kinda deserves a separate thread.
Railway Man Paul, I think what I did was write without clarity.What I meant was this, for the passenger ride issue:Track is far and away the primary cause of poor ride quality. Bogies are usually only a cause of poor ride quality if they are not maintained, or a bad design to begin with. Poor bogie designs and unmaintained bogies usually are a result of trying to design and maintain a bogie that will make-up for poor track quality. In other words, if the track is poor quality, it's hard to make up for it with a better bogie. It's asking too much of the bogie. There's been a lot of effort to try to solve the track problem with a bogie solution; I'd rather just solve the track problem with the track.There are some bogie designs that have demonstrated poor tracking qualities. There's usually not much that's feasible to improve them other than scrap them and start over, or stiffen the ride so much that while the bogie becomes safe, the ride quality goes to hell.As far as freight bogies, it's not feasible to build and maintain freight cars with 286K axle loads to run on plus-90 mph track without severe economic penalties. The rail profile desireable for high-speed passenger is not the rail profile desireable for heavy freight. They're fundamentally incompatible. The rail surface required for a good ride quality for passenger is not the rail surface that can be obtained if freight runs on the same line, without a very high maintenance cost and greatly diminished rail lifespan. I suppose it might be possible to build a freight bogie that didn't kill rail on a high-speed rail line, but I don't think anyone would want to pay for it. The economics all point toward separate track structures. This is not to say that a high-speed passenger train cannot "get off" the high-speed line and "run conventional" on a line that carries freight, as you would commonly find in last-mile situations in a major terminal, where there isn't spare right-of-way laying around to place a new passenger track onto, or at a major river crossing. Of course, the passenger train speed will be knocked down to 79 mph (or much less) and the ride quality won't be so hot. This is the near-term solution I think we'll see in many corridors, because the cost per mile to build new HSR passenger train infrastructure in a city center can easily be 10-30 times the cost to build it out in the suburbs or farmland between cities. RWM
Paul, I think what I did was write without clarity.
What I meant was this, for the passenger ride issue:
As far as freight bogies, it's not feasible to build and maintain freight cars with 286K axle loads to run on plus-90 mph track without severe economic penalties. The rail profile desireable for high-speed passenger is not the rail profile desireable for heavy freight. They're fundamentally incompatible. The rail surface required for a good ride quality for passenger is not the rail surface that can be obtained if freight runs on the same line, without a very high maintenance cost and greatly diminished rail lifespan. I suppose it might be possible to build a freight bogie that didn't kill rail on a high-speed rail line, but I don't think anyone would want to pay for it. The economics all point toward separate track structures. This is not to say that a high-speed passenger train cannot "get off" the high-speed line and "run conventional" on a line that carries freight, as you would commonly find in last-mile situations in a major terminal, where there isn't spare right-of-way laying around to place a new passenger track onto, or at a major river crossing. Of course, the passenger train speed will be knocked down to 79 mph (or much less) and the ride quality won't be so hot. This is the near-term solution I think we'll see in many corridors, because the cost per mile to build new HSR passenger train infrastructure in a city center can easily be 10-30 times the cost to build it out in the suburbs or farmland between cities.
RWM
I wasn't aware that there was a difference in optimal rail profile for freight and high speed passenger.
Even so, I think the more pertinent question is whether 110-150 mph passenger services can co-exist with freight.
It's mostly a matter of traffic volumes, axle loads, and speeds. Freight is at one end of the spectrum with high axle weight and moderate speed; and passenger at the other with the exponential effect of speed. At the end of the day, either one can degrade surface and line more than the other. Running passenger trains requiring Class VI or higher standards simply is going to cost more to maintain. Are the volumes of traffic condusive to sharing infrastructure costs or not?
Most high-speed lines have evolved as trunks where trains do get off and run at more conventional speeds for a distance.
The 3-piece freight truck is adequate for the speeds freights operate. Freight railroads don't want to be resurfacing and relining tracks any more often than necessary. It's as easy to surface and line to Class VI or better as Class V, taking longer to degrade and avoiding more frequent maintenance. Track must be maintained to a pretty high level for 60-70 mph intermodals and other priority trains to minimize rapid degradation and more frequent maintenance.
If higher freight speeds are desired, more expensive features of high speed passenger trucks can be adopted and weights on axles can be reduced along with trains designed for less drag.
Furthermore, I rode the BNSF between Naperville and Chicago recently; and the ride was decent, if not as smooth as Europe. It's a lot better than the CTA. Even the newly rebuilt subway tracks on concrete "ties" cast in place on the tunnel invert get rough from slight mis-alignments above 35 mph.
I think there needs to be an understanding of what levels of comfort we are talking about . I would certainly expect a much higher level of comfort on an inter city train than on a local or a commuter train. In Europe the inter city trains have a much more comfortable seating in 2ND class than do other trains. I didn't see any 3-2 seating on inter city trains, common on lesser trains.Most business travelers in Europe travel in in what they call standard class now. The train trip between Paris- Lyons or Frankfurt- Munich is a long trip and rates a decent seat. They have premium standard class which caters to business. The business traveler will always be the backbone of any inter- city service.
The type of car, Superliner or regular coach, brings up another point not brought up in these discussions so far. That is: why is the person traveling, why are we running this train, and for whom. Yes, it is all part of marketing but we the type of service being offered will dictate the equipment and speed. Just moving people from place to place is the most basic of service, needs only a car with decent seating; if it is commuter, up to two hour ride, one type of seat, but if long distance, then more comfortable seat is needed. If long distance, then is the service for business or tourist? Each has different needs of speed and amenities. How important...and different...is the scenery for a tourist or for a businessman? I could go on and on, but you get what I mean. The reason for the traveling as well as the travel conveyences as part of marketing has to be considered in determining any service, and more so with high speed if only to determine return on investment (dollars and cents, and other factors).
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blue streak 1I realize that you do not want to ever put freight on HSR. However you may want to put full bi-level conventional passenger equipment on that line since the axel loading will only be a small amount more. I may be wrong but the Victorville - Las Vegas proposed clearances (including CAT) will not clear superliners. Does anyone know for sure?
I realize that you do not want to ever put freight on HSR. However you may want to put full bi-level conventional passenger equipment on that line since the axel loading will only be a small amount more. I may be wrong but the Victorville - Las Vegas proposed clearances (including CAT) will not clear superliners. Does anyone know for sure?
I'm not so sure you want to run Superliners or California Cars on a high-speed line. The weight per axle is more than twice that of a high speed train. I am certain that the vertical clearances should allow for a double-deck TGV or Shinkansen and 25-50kV electrification.
Las Vegas doesn't seem like a high-volume destination where HSR would be viable with trains only every 1-2 hours without a dinner and show included. This would be like the NEC with fewer Acelas and no Regional, long distance, or commuter services to support the infrastructure.
A more conventional (110-125 mph?) train on a high speed line from LA to Victorville could continue to Las Vegas over the existing line. Hourly expresses to San Francisco, Richmond, and Sacramento and a Central Valley local might be fleeted to allow a conventional train to Las Vegas. Dual-powered gas turbine-electric/electric high-speed trains would be needed to fit in with more high speed traffic. It's a question of tailoring the application to the need.
Railway Man Unsatisfactory ride quality is usually a result of (1) poor surface and line (2) rough wheel-rail contact area characteristics. Bogie design and car geometry can create problems too, but usually those are all-or-nothing phenomena, i.e., either "it works" or "it doesn't work."
Unsatisfactory ride quality is usually a result of (1) poor surface and line (2) rough wheel-rail contact area characteristics. Bogie design and car geometry can create problems too, but usually those are all-or-nothing phenomena, i.e., either "it works" or "it doesn't work."
I think I am mixing up two kinds of bogie problems.
In your technical paper, you mainly talk about bogie problems on the high axle load freight cars. High axle loads are given as a reason for the rail surface to take a pounding, and a high axle load freight car with the trucks out of spec give the rail surface a real pounding. I am thinking that the maintenance cost issue you were talking about was one of keeping the freight car fleet up to a high enough standard so they don't damage the rails in a way to impede passenger service at 90+ MPH on the same line.
The second kind of bogie problem is the one I was thinking about on the passenger coaches. You suggest that the passenger bogie is an all or nothing proposition -- you either run safely at a given speed or you are above the critical speed and you jump the tracks.
There are the ride quality problems related to rough track, but there is also evidence of ride quality problems related to bogie stability at speeds below where you jump the tracks. I had read a discussion in a British journal on railroad technology where the authors were relating dynamic stability to 1) the rail profile, 2) the wheel profile, and 3) the directional compliances (spring rates) in the bogie, and they were complaining that spotty maintenance of a certain class of coaches created the situation where you could be OK in one coach and bounced around in another coach. I have also wondered if many reports of rough riding on Amtrak might have to do with worn journal guides more than particularly rough track.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
High speed rail is not a stand alone service. To take advantage of the speed it must have few stops. The smaller communities must be served by a local or regional train. The local train can use the same track, and use as much speed as it's many stops permit. The local stops need a siding, so that the high speed train can pass the local without slowing down. With stops in only the larger cities, much longer distances become a reasonable option. Only the high speed train needs to be federally funded. The locals should be run by the states and the stations operated by the communities which they serve.
Dave
Lackawanna Route of the Phoebe Snow
Dakguy201Thanks to RWM for that reference to information on rail deformation/failure. Do 315,000 lb capable railcars have 4 or 6 axles? The reason I ask is that (to take one example) Union Pacific shows substantial portions of their system as 315,000 capable on the chart on their website. This includes the entire Overland Route west of Omaha, the Sunset Route as far east as Houston, the Salt Lake to LA link, and the Portland to LA line. If those cars are 4 axle, this railroad, and I assume the other Class I's, are continuing to push the envelope regarding what can be done safely with their freight trains. In my mind, this reinforces the point that to get to anything approaching high speed rail you have to have seperate tracks.
Thanks to RWM for that reference to information on rail deformation/failure.
Do 315,000 lb capable railcars have 4 or 6 axles? The reason I ask is that (to take one example) Union Pacific shows substantial portions of their system as 315,000 capable on the chart on their website. This includes the entire Overland Route west of Omaha, the Sunset Route as far east as Houston, the Salt Lake to LA link, and the Portland to LA line.
If those cars are 4 axle, this railroad, and I assume the other Class I's, are continuing to push the envelope regarding what can be done safely with their freight trains. In my mind, this reinforces the point that to get to anything approaching high speed rail you have to have seperate tracks.
4-axle. Look just like a 286K car but have larger bearings and wheels, and a slightly larger bogie to carry them. 315K is not a safety issue, it's an economic issue. So far, widespread use of 315K has been deemed uneconomic.
Dakguy201
It certainly sounds like separate trackage is an absolute requirement, even for sub-HSR service. We also need to make wise choices as to locations for upgrades to a viable passenger service. A minimal population density rules out most long-distance (~1000 miles?) runs for now. But clearly routes beyond the "lots of promises, disappointing performance" NE Corridor are needed.
C&NW, CA&E, MILW, CGW and IC fan
Two opposing principles at work:
Finding the right balance - ay, there's the rub.
I don't think you need 23'4" overhead clearance for a high-speed passenger line, because you really do not want to ever put freight on it. But that's just a minor point to your very appropriate basic premise that the technical standards and details need to be thought through before shovels are turned.
RayG8 HSR viability involves and awfull lot of questions and points of view from competing interests. At the bottom of all this is the question of neccesity. Is it really needed between say LA and vegas? Or is this just politics that will leave the public (non railfans) seeing just more money poured into a project that might well leave the industry with a real PR problem, kind of the way a lot of people see AMTRAK.
HSR viability involves and awfull lot of questions and points of view from competing interests. At the bottom of all this is the question of neccesity. Is it really needed between say LA and vegas? Or is this just politics that will leave the public (non railfans) seeing just more money poured into a project that might well leave the industry with a real PR problem, kind of the way a lot of people see AMTRAK.
Many wise people have posted on this forum that not all HSR projects will pan out. How true. However the article on Friday Jun 4th train's newswire of a bonding proposal will probably go through given the present polical climate. If it does and many people think it will then HSR will be on an unstopable fast track. The politics are very great and we need to prevent as much as possible any thing that will be bad publicity.
The thing is that all of us posters need to be is very critical of the proposals and not let restrictive engineering shortcuts be implemented causing a permanent restriction to HSR. Shortcuts can cause a permanent loss of potential traffic. Two examples are THE tunnel (NJ TRANSIT's hudson river tunnels) which probably already is too late to be made AMTRAK friendly and the proposed Victorville - Las Vegas line specifying only 16' 9" clearances (should be 23' ?). We should all be contacting the FRA to have them specify the 23' clearance! ( RWM spoke of this earlier) Do we believe that HSR intermediate stations should have separate station tracks to allow overtakes of Expresses around Regional trains? Will speed restrictions be eliminated to HSR can go from Conventional to Emerging to Regional to Express? The possibilitys of bad decisions are very lenghty and our vigilance will be very important.
But Paul, your car is your private property to care for as you wish...there are many who don't pay attention to their cars until the tires go flat or they're pulled over and ticketed for unsafe tires. But more importantly my point goes to public projects like highways, water systems, and railroad and related equipment. Hundreds of years since the first laying of water pipe in many cities is an example: they've lost the plans; its working so don't fix it; or yeah, they know its there but don't know where it comes from or where it goes but as long as nothing happens its ok. Then in the dead of winter one finally splits open and there is a real problem. Instead of having routinely replaced and upgraded we react to catastrophe. Highways are another problem: we build them for 5 ton trucks and a 20 year life span. Next we know there are 20 ton trailer trains on a 50 year old highway that has only been repaved a couple of times. On the railroads, the GG! and the DL&W MU's both gave service well beyond thier initial 20 year expected life span, way beyond, before real replacements were considered, then needed.
Paul, you're getting into more than I can distill, mostly from lack of expertise on my part. I can offer only some broad guidelines.
Unsatisfactory ride quality is usually a result of (1) poor surface and line (2) rough wheel-rail contact area characteristics. Bogie design and car geometry can create problems too, but usually those are all-or-nothing phenomena, i.e., either "it works" or "it doesn't work." Bogie design can be optomized for a track with good rail-wheel contact and good surface and line, or optimized for bad, but it won't do both. The bogie has to do a lot more work when surface and line and rail surface is bad, and more work means heavier components are required (bad), more wear is generated (bad), more heat must be wasted (bad), more vibration is set up (bad), all of which degrade bogie life and bogie work output dramatically. Poor surface and line is usually a subgrade and drainage issue at its root; if you do not have either, you can never hold surface and line for very long. Rough rail-wheel contact area problems are usually a result of damage to the rail head by heavy axle-loadings, or bad metallurgy of the rail, or poor grinding technique and design, or lack of maintenance of the wheelsets.
U.S. and European/Japanese rail economics have very different business models. One of my mentors, who has spent now more than 40 year in the industry including more than 10 years leading the establishment of rail freight systems in Europe, noted to me once the following. "You can sum the differences by saying that the U.S. has an excellent freight rail system that does a little bit of passenger not very well. Europe has an excellent passenger-rail system that does a little bit of freight not very well." I usually don't use that characterization with non-rail industry people, because it's red meat dragged in front of ideologues and hair-splitters. But its fundamentally true. Europe asks for different things from its rail system. That doesn't mean one or the other is "right" or "wrong" but if we don't understand it and accept it, we'll just go around in circles and do stupid things, I think.
As illustration of how this works out, because U.S. practice is basically a heavy-haul practice based on the existence of cheaply purchased, cheaply-maintained free-runner freight cars, it emphasizes maintaining the rail and not the wheel, because its easier to control the rail and ignore the wheel. Whereas European/Japanese practice is basically a passenger practice, with the equipment making frequent visits to the shop if only for cleaning, they can emphasize maintaining the wheel and not the rail. The preference can be turned around and done the other way, but that has ramifications on almost everything about the equipment, track, and operating and maintenance practices, and by extension the economic and business model.
There has been some searching around the margins for alternative solutions such as you describe, but so far no one has demonstrated any significant, obvious, benefit to the stiff axle, two-axle bogie, flange on the inside of the wheel architecture worked out in Britain and the U.S. prior to 1850. It would take a staggering amount of R&D work to take an alternate architecture to commercially implementable stage, and no one I know has seen any obvious inctentive to do so for high-speed rail or freight rail. The current architecture works extremely well, and is simple, cheap, and its characteristics studied for a long time. It bothers some people I work for that anything worked out so long ago could possibly still be any good. Whether they get that attitude through arrogance about how smart people are now compared to a century ago, or absolutely no understanding of science and engineering, I do not know. I just smile, and don't waste my time reminding them that the fundamentals of farming were worked out 6,000 years ago and somehow we haven't all starved to death in the meantime. Patrick Smith, the airline captain who writes the "Ask the Pilot" column, noted the other day that the architecture of the current state-of-the art jet transport was essentially designed by the Wright Brothers. Long story short, I am not professionally compelled to investigate alternative guideway solutions such as Maglev or monorails. Just contemplating the amount of money it would take to even concept a new architecture, and understand its economic differences with the current architecture, and run down its failure modes and safety problems, makes me depressed.
Thus, I don't think we are likely to see any revolutionary changes in the basic architecture. There is still a great deal of opportunity for improvement in the existing architecture such as better rail metallurgy, better measurement and fault detection systems, and ways to automate maintenance and focus maintenance at an ever finer grain, that I think we'll continue to steadily slice cost out of the system by 2-3% per year. In other words, every 20-25 years we'll double the work output of a rail system for the same price input.
There's no question that Europe and Japan have vastly more experience than North America in high-speed rail technology. That's why we borrow from them heavily. Similarly, North America has vastly more experience in heavy-haul technology, which is why the heavy-haul systems worldwide are all North American practice and we regularly go overseas to consult to them. The rail community is global in its outlook and greedy in its practices, appropriating and adapting good ideas wherever it sees them. I see no risk that the U.S. as it embarks on a high-speed rail program will not leverage foreign practice 100%. There's no not-invented here syndrome in my world. As illustration, flash-butt rail-welding was developed in the Soviet Union -- that didn't stop anyone in the non-communist world from recognizing its value and borrowing it immediately.
henry6 "Wear out" or "rolliing contact fatigue"! Doesn't matter. Americans build things, put a "life span" on them, then expect them to last forever even without maintenance. Talk railroads and trains, highways and cars, or pipes delivering water to your house, its all the same thing. "Life span" has become a term for tax write offs and depreciation rather than a guage which to use to maintain, repair, or replace. So when at the end of the "life span" we are suprised that it didn't and won't last forever and ever as is and that it will cost us to rebuild or replace.
"Wear out" or "rolliing contact fatigue"! Doesn't matter. Americans build things, put a "life span" on them, then expect them to last forever even without maintenance. Talk railroads and trains, highways and cars, or pipes delivering water to your house, its all the same thing. "Life span" has become a term for tax write offs and depreciation rather than a guage which to use to maintain, repair, or replace. So when at the end of the "life span" we are suprised that it didn't and won't last forever and ever as is and that it will cost us to rebuild or replace.
Let's take something as prosaic as tires on cars. I am an American. I own and operate a car. I do not in any way expect the tires to last forever. I count on having to replace them with new tires every however many miles that kind of tire is supposed to be good for. I make allowances for the kind of driving I do on how long the tires last. I do rigorous maintenance on the tires, checking their pressure frequently and taking them in for "flat repair" if they don't hold pressure.
When the tires wear out, I do not trade in the car but I simply buy new tires. These new tires are a big expense, but they are an expense I can plan on given that tires wear at a certain rate.
I do other kinds of maintenance with regard to the tires. If it were up to me, I would do frequent wheel alignments because I am very fussy about details of the car's handling and whether it has a slight pull and whether it resists the pull from crowned roads and cross winds. My alignment is probably out-of-whack most of the time because where I live has roads that look like the craters on the Moon. This is not the result of the City not doing road maintenance because gosh knows how many road contruction zones there are or how much I pay these days in property tax. A lot of this has to do that there is a lot of building construction where I live and constant and chronic tearing up and patching roads to put in utility services.
My car maintenance guy as well as a former student of mine who now works for Toyota convinced me that the thing to do is more frequent tire rotations instead of wheel alignments. Given that the wheels will never be held within factory specs, the tire rotations spread the wear around and give me a lot more mileage out of the tires. I follow this advice, perform this type of maintenance, and get good service from my tires. Am I an "ugly American" for taking this "maintenance shortcut" on the advice of experts (the owner of a car repair shop and and engineer at Toyota's Arizona proving ground)?
Now suppose there were something either about the tires, the condition of the roads, or the design of the car that tires were blowing out at random intervals with a chance of nearly 1 over the 50,000 mile rated life of the tire. Would I be unhappy about this state of affairs? You betcha!
Suppose someone came along and told me that I had to do daily inspection of the tires and that if I saw a hairline crack, I would have to pitch the tire and get a new one. Would I be unhappy? Would this make me an "ugly American" who sits on a sofa eating junk food in front of cable TV in all my waking off-work time? A person thoroughly unlike those healthy, slim, open-minded, maintenance-minded, cheerfully tax-paying, train-riding, philosophically flexible Europeans?
Now for all of the talk about how Americans are this and Americans are that and America is falling behind the Europeans in railroad tech, here is this fellow who comes along and explains the results of research done on these shores on railroads. OK, OK, if you follow the link to the paper, the work was done in Canada.
So someone new comes along and shares with the passenger train advocacy community about a new problem relating to the high axle loads and level of maintenance of equipment used in freight service and how this problem affects passenger trains. We are collectively going to run this fellow off this forum because we in the passenger train advocacy community haven't had a new idea since the inception of NARP 40 years ago and we aren't about to accept any new ideas about passenger train operations either.
Ride quality is affected by the following: Quality of the surface and line -- it is very hard to maintain this for high ride quality (not safety) on a shared freight/passenger line with high freight axle loadings and high freight gross tonnage, one or both of which obtains on almost all U.S. lines (which are freight lines, first and foremost, outside of the center tracks on the Northeast Corridor) but not on most European passenger/freight lines. Quality of the rail geometry and surface -- again, very hard to maintain this to a very high ride quality on a shared freight/passenger line with high axle loadings and high freight tonnage. See above. Quality of the wheel geometry and bogie maintenance -- must be maintained to a very exacting standard to obtain high ride quality, and if the rail surface and line, and rail geometry, has heavy freight use, the cost for this skyrockets. So it's not attempted, anywhere in the world.
Ride quality is affected by the following:
I remember one of my advocacy colleagues remarking about a Superliner car about how such a "big thing" is kept on the rails by "those tiny flanges", and it was a surprise when I pointed out that it wasn't the flanges that kept it on the rails apart from as a backup system.
Apart from Talgo, the way railroad cars are kept on the tracks is that there is a solid axle connection between the two wheels, and the wheels have a conical taper, the net effect is that when an axle slides off to one side relative to the railhead, one wheel has a bigger effective diameter at its contact patch and the other wheel has a smaller effective diamer, steering the axle back towards center. It is well known, however, that this arrangement is kinematically unstable -- the axle will steer back and forth in a sinusoidal pattern without the amplitude of that sinusoidal weaving back and forth between the rail ever diminishing. So axles are combined into trucks or bogies as they are called to damp that oscillation.
It is also known that even when wheels are combined into bogies, there is a certain critical train speed where those oscillations will grow until they meet other bounds such as flange contact or possibly even derailment. My understanding is that operating below but close to that critical speed can amplify track irregularities and produce a rough ride.
Why this critical speed phenomenon should occur for a purely passive system -- why a system with only mass, spring, and damping can have oscillations that don't damp down -- seems a bit of a mystery. But the system is not passive as energy is put into the train by supplying motive power to push it down the track, and the friction characteristics of the wheel-rail contact are regarded to be the mechanism by which tractive effort is converted into the oscillations.
My first question to RWM is to what extent are ride quality problems in passenger equipment related to this dynamic instability effect and to what extent are they related to simply rough track, much as a bumpy road produces a rough ride in a car operated at speeds well within its stable range?
My second question relates to what I have seen written on dynamic instability, and the variables I have seen considered are the rail profile (maintained by rail grinding), the wheel profile (maintained by wheel grinding, and I understand that TGV and Shinkansen do frequent wheel grinding to maintain wheel profiles), and the suspension compliances (related to what you called bogie maintenance). My question is, is the track compliance (relating to factors such as ballast condition, wood vs concrete tie, type of rubber pad used with concrete) also an important variable in dynamic instability and the critical speed?
My third question is whether keeping a high critical speed and the related issue of ride quality is purely a matter of track compliance, track geometry, wheel profile, suspension compliance and maintaining all of these to required tolerances or if some progress has been made on forgiving design?
The first group of engineers to look at this systematically were the Japanese with their pioneering Shinkansen, and their efforts were a combination of high engineering standards, rigorous maintenance of track and vehicles, and increased spring stiffness against turning of the bogies. The second group of engineers to look at this to my knowledge were the British with their Advanced Passenger Train project. I had heard that they had something called a Heumann wheel profile, where the specified wheel profile was closer to the kind of hollow you get with the natural wear pattern, and that they were considering a bearing to allow the two wheels to rotate independently in the manner of Talgo? The idea was to come up with suspension designs and wheel profiles that were more forgiving of wear -- did anything ever come of it?
There are also a number of guided-axle systems -- notable Talgo with independent wheel rotation, the Alan Cripe Turbo Train with a solid axle, and various European patents on "forced steer" conventional two-axle bogies. The idea is that one could suppress wheel hunting and raise the critical speed by increase the spring resistance to axle self-steer, but provide enough forced-steer alignment of the wheels to reduce the increased wear levels that would result. Has anything come of that -- does any of that work?
My father Veljko Milenkovic had worked at GATX in the early 1970's on some concepts related to dynamic stability. One of his pet peeves (like many dads, he was vocal about such things and I grew up hearing about them) was railroad companies insisting on bi-directional trains. In his opinion the dynamic stability problem could be made to go away with some kind of semi-trailer arrangement like the 1930's version of Talgo as well as the C&O's early 1950's Train-X prototype. I remember him ranting "They don't design your car to be bi-directional! You don't drive your car at highway speeds in reverse!"
Another idea is one on which he shares a patent with a colleague at GATX, and this patent was developed for the ultra-wide gauge RRollway concept of a railway drive-on drive-off high-speed automobile ferry substitute for toll roads. The system is that you would do away with the solid axle connection, the wheel taper, or even flanges, and the bogie would be guided by side rollers gripping one of the rails. The system was in a way like the Alweg Monorail, but instead of multiple wheels contacting a single concrete beam from the top and sides, you would have steel wheels doing the same thing to one of the two steel rails and have the other rail free to bear the weight of the other wheel.
This roller guidance system is something he showed mathematically to solve the critical speed problem, and this system is a departure from conventional railroading but not as radical as Alweg Monoroal or maglev. But like those other systems, there is additional complication in the track switch -- you would require a fully movable frog as well as switch point -- these may even be described in that RRollway patent. But at least this system would be railway compatible -- if it is in standard gauge, you could dispatch a road switcher locomotive to rescue a stranded HSR train, something that is an issue with Alweg, maglev, and the like.
Why anyone in the advocacy community should even care about all of this escoteric tech is that it affects the economics and practicallity of HSR. My understanding is that HSR is pretty much the Japanese model of high engineering standards, high levels of maintenance to maintain those standards, and more or less conventional railway equipment. I am curious if in 40 years since the pioneer Shinkansen whether there have been significant technological improvements that would allow doing more with less - operating at high speeds without the high maintenance expense.
Dakguy201 Could we please have an explanation of just what "rolling-contact fatigue" is? If the cause of such fatigue is the heavy axle loadings of today's freight cars, why is it noticable on lightly loaded passenger cars -- is it somehow a permanent rail deformity? Is this a cummulative problem in that a given rail has sort of a lifetime limit of "x" number of 71,500 pound axle loads?
Could we please have an explanation of just what "rolling-contact fatigue" is? If the cause of such fatigue is the heavy axle loadings of today's freight cars, why is it noticable on lightly loaded passenger cars -- is it somehow a permanent rail deformity? Is this a cummulative problem in that a given rail has sort of a lifetime limit of "x" number of 71,500 pound axle loads?
The following AREMA paper goes into detail (I've summarized below). http://www.arema.org/eseries/scriptcontent/custom/e_arema/library/2004_Conference_Proceedings/00011.pdf Skip down to the illustrations on page 22 and you'll see graphically why RCF leads to poor passenger vehicle ride quality. RCF is a damage phenomena that results from overstressing of the rail material caused by repeated intense rail-wheel contact cycles. The results appear on the rail surface, usually on the head and/or gauge corner, as shelling, head checks, squats, or corrugation. All will give a very poor ride quality, causing both loss of smoothness and increase of noise. This failure mode appeared in the 1990s and has become a primary mode of rail failure. It was implicated as the cause of the Hatfield derailment in 2000 in Britain, and by the FRA in more than 100 derailments in the U.S.
The #1 cure for RCF in a passenger vehicle environment is eliminate freight from that track by either diverting the freight to truck, or building a separate track for freight. Other solutions are grind the rail head and gauge corner frequently and precisely, control wheel geometry precisely (with frequent turning cycles), detect bad-actor freight wheelsets and bogies before they get onto the track and damage it (one trip, one bad axle, can do severe damage). These cures are costly. It's why freight is only barely compatible with 90 mph passenger in the U.S., and incompatible with plus-90 mph.
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The one thing I admire about the Europeans is that they know how not to throw out the baby with the bath water: they keep and respect the good of the old while still progressing with new techonologies, philosophies, and concepts.
Railway Man In the 1960s the predominate rail failure mode was "wear out." Today the predominate rail failure mode is rolling-contact fatigue, which is a major reason why you observe lower ride quality -- we're at the very upper end of the rail material capability on a freight/passenger rail line with U.S. axle loadings.
In the 1960s the predominate rail failure mode was "wear out." Today the predominate rail failure mode is rolling-contact fatigue, which is a major reason why you observe lower ride quality -- we're at the very upper end of the rail material capability on a freight/passenger rail line with U.S. axle loadings.
This recurring statement about HSR only for the rich: I must challenge the accuracy of that. I don't know about some countries, but in Germany the ICE ridership is certainly not just the rich. They seem to come from most of the citizenry, probably more urban than rural. And it's not like Germans don't have cars, including expensive ones they like to drive as fast as they can go. Everybody rides trains because they are convenient ,comfortable and pretty fast. And not necessarily cheap; often airfares are as cheap or cheaper.
On this thread's first couple of pages there were some posts that mentioned rail, and high speed rail in particular, passengers tend to be relatively well to do. The impression I got was that those were complaints that middle class and poor were being short changed, or discriminated against, somehow.
If high speed rail is a money maker via fares, then I don't see why the fact that rich people use it vs poor people is a bad thing, or at least the rich are paying their way appropriately. And if it's part of a subsidized system, then the putative rich fare payers would be cross subsidizing the other parts of the system that the less rich travelers use.
Also no man is an island, look at the big picture, what alternate transportation would the rich bloated plutocrat take otherwise, and what is that mode's cost or subsidy?
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Phoebe Vet Anyone who reads these knows that Sam and I don't often agree, and I hope our discussions don't sound like there is any personal animosity.
Anyone who reads these knows that Sam and I don't often agree, and I hope our discussions don't sound like there is any personal animosity.
I think I mentioned before I wonder if you and Sam are the same person with two different login names, I rarely see a post from one of you without a rebuttal from the other. I don't follow a very scientific sampling though, being a trolley fan I lean towards the transit and passenger forums. Maybe I should check out some of the teakettle forums, there might be a few posts about steam trains there where you and Sam agree.
Of course for a truly hi-speed line in excess of 150 mph the newer concrete slab system is used (eg., on the new Nuremburg-Munich line) to elim,inate problems with flying pieces of ballast. Pretty expensive, though. But if we want a usable system, we will need to pay. For some runs, a pretty fast, but not truly hi-speed line might suffice at a lower cost. Frequency of service is at least as important as top or average speed.
henry6I also have to get in line behind concrete ties. Riding all NY Metro area rail lines, inlcuding subways, I am of the impression that concrete ties are quieter adn work better than wood; and, except for a bad batch of concrete ties both MNRR and Amtrak got, they seem to last longer
I also have to get in line behind concrete ties. Riding all NY Metro area rail lines, inlcuding subways, I am of the impression that concrete ties are quieter adn work better than wood; and, except for a bad batch of concrete ties both MNRR and Amtrak got, they seem to last longer
Correlation is not necessarily causation.
I don't know what it is you want to accomplish. If you want to know what I know, it's free for the asking. If you don't want to know what I know, I will politely stop sharing (nothing personal and no offense taken). But if you want to tell me that what I know "I don't know" because your observations lead you to different conclusions, I'm sort of nonplussed, because you're not using terms I can relate to. I am not and could not disagree with your observation that the lines laid with wood ties seem to be noisier than the lines laid with concrete, just pointing out that rail, wheel, surface, line, subgrade, and fastener conditions might be very different on the different lines. How are you certain that it's the concrete vs. wood that's the cause?
schlimm RailwayMan:You'll find I have agreed with you about the need for dedicated passenger-only lines. However, I doubt if everyone else with fast trains (eg., Germany, Japan,France, UK and China) is using concrete just to avoid maintenance. The ride simply is much smoother and quieter. BTW, I recall riding American trains on shared right-of-ways in the 60"s on the IC, ATSF and CB&Q. Very fast (80 +) and smooth! Of course freight cars had lower, though hardly low tonnage then.
RailwayMan:
You'll find I have agreed with you about the need for dedicated passenger-only lines. However, I doubt if everyone else with fast trains (eg., Germany, Japan,France, UK and China) is using concrete just to avoid maintenance. The ride simply is much smoother and quieter. BTW, I recall riding American trains on shared right-of-ways in the 60"s on the IC, ATSF and CB&Q. Very fast (80 +) and smooth! Of course freight cars had lower, though hardly low tonnage then.
Let me give you some background on me, I've been in the railway business both in the U.S. and abroad for more than 25 years now. I've hired (and fired) railway engineers from Britain, Canada, the U.S., India, and several middle-eastern countries for more than 10 years now. I'm bemused by the suggestion that we're parochial or ignorant of foreign standards. When I was in grad school most of my research assignments used Indian rail journals because they were really into the science.
Avoided maintenance cost and disruption to passenger schedules is 99% of the reason why a passenger rail line chooses concrete. The other 1% is initial delivered cost (hardwood ties are more expensive than wood in all the areas of the world where hardwood forests never existed or have all been chopped down).
The axle loadings in the 1960s were rarely greater than 55,000 lbs. Axle loadings today are 71,500 lbs. But that's not just a proportional difference. Much, much more is being asked of the rail and wheel metallurgy today. In the 1960s the predominate rail failure mode was "wear out." Today the predominate rail failure mode is rolling-contact fatigue, which is a major reason why you observe lower ride quality -- we're at the very upper end of the rail material capability on a freight/passenger rail line with U.S. axle loadings.
Gross tonnages on almost every high-use U.S. rail line are two to five times greater, or much more, than in the 1960s. But the number of tracks are the same or fewer on those lines. The track is being asked to do much more than it was then. It's not surprising that ride quality has declined greatly.
Another major difference in ride quality between then and now in the U.S., which is probably not known to you, is the change in rail section. In the 1960s most U.S. passenger-carrying rail lines were laid with 5-1/2" base rail in the 115-lb. size range. Today, those same lines are laid with 6" base, 136 lb. or 141 lb. rail, necessary to support the higher axle loadings we have now. There is a significant decrease in ride quality with the heavier rail sections because it is so much stiffer and less forgiving of all the imperfections in surface and line. The standard European rail section, by contrast, is UIC 60, which is very similar to our current 115-lb. rail section. It's a great section for high-speed passenger but not so hot for heavy freight.
schlimm Railway Man "This has 0% to do with European engineering. It has 100% to do with what the respective rail lines are being asked to do."Yes and no. In Germany, almost all track, freight or passenger, has concrete ties. On the BNSF Metra line, which once hosted Zephyrs, it remains aged wood ties. Hence the terrible ride which obviously can't handle even 79 mph. So what we need is frequent service on separate, dedicated passenger lines, high speed or less-than-high-speed, if we want passenger service that people will use.
Railway Man "This has 0% to do with European engineering. It has 100% to do with what the respective rail lines are being asked to do."
Yes and no. In Germany, almost all track, freight or passenger, has concrete ties. On the BNSF Metra line, which once hosted Zephyrs, it remains aged wood ties. Hence the terrible ride which obviously can't handle even 79 mph. So what we need is frequent service on separate, dedicated passenger lines, high speed or less-than-high-speed, if we want passenger service that people will use.
No sir. Wood ties will give you a much better ride than concrete. Concrete ties are more noisy, harder to maintain in good surface and line, and less resilient, which makes them much more demanding about surface and line. There is nothing "aged" about those wood ties in that particular line, either, it's maintained to FRA Class 5-plus, which means on average those ties will be about 10-15 years old, with some that are new and some that in the 20-25 year age. The ride is safe for 79 mph but it may not be as comfortable as you wish. There is nothing old fashioned about wood ties, either. From an engineering perspective they are an either/or for concrete. The decision of which to use is local delivered cost, and costliness of track windows for replacement. Railways such as light-rail lines or high-speed rial lines often prefer concrete because they want to have less-frequent work windows for replacing ties, which in an urban setting, on an elevated track, or in a tunnel, and with very narrow work windows late at night and on weekends, is a very big deal. Many 90 mph-plus rail lines with excellent ride quality are laid on wood throughout the world.
You can't obtain very high ride quality, and share a line with heavy freight trains, without spending an ungodly amount of money. That's been well known in the world-wide rail community for more than 100 years. Railway engineering is an international community with no secrets. We all read the same journals, go to the same conferences, and hire the same scientists.
I don't have any problem with anyone observing that the ride quality experience of many U.S. passenger trains is inferior to that of many European or Japanese trains. I've made the same observation myself and so has just about everyone, it's not novel to you and I. But to ascribe the difference to an inferiority of U.S. engineering, or U.S. knowledge, or U.S. practices, is incorrect. The difference is that the U.S. asks its railway system to do different things, and deliver different results. The U.S. is not asking its rail system to deliver anything other than low-cost, high-volume freight capacity, and provide some capacity for passenger trains on a significantly less-than-actual-cost basis. If the U.S. is to ask its rail system to deliver high ride quality for passenger trains too, then it will have to pay for it with separated passenger lines that heavy freight trains don't beat up. That is exactly what the U.S. railway industry and the U.S. DOT have agreed will need to happen, and that's what President Obama is proposing to pay for with high-speed rail funding. In the meantime, for us to expect to have our cake and eat it too - and then blame the freight rail industry for not giving us something for nothing, or the rail engineering profession for being stupid -- is a bit rich.
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