As traffic grows, so does the case for a larger gage.
As a rail system grows, so does the case for not changing the gage.
OldArmy94I was curious as to what type of research has been done regarding gauges. Obviously, we have what we have in North America due to a lot of reasons, but I wonder as to whether or not serious studies have ever been done to determine what is the "perfect" gauge in different settings. If we were to start over and build our railroads from scratch, and we could build locos and rolling stock in any gauge, too, what would decide to use? I just want to get input from folks, especially those with an engineering bent. All opinions are welcome, informed or not. :)
What we now call "standard guage" became the "standard" largely through historical accident (George Hilton's book on narrow gauge railroads has an excellent discussion of this issue). Essentially, the commercial need for individual railroads to be able to seamlessly interchange with other railroads as part of a national rail network trumped whatever theoretical engineering advantages different guages might have. The narrow guage railroads popular in the late 19th century learned this the hard way. So did the Erie with its 6 foot wide gauge somewhat earlier.
If we were building the rail system from scratch today, a somewhat wider guage might be chosen. One of the past presidents of the BN once suggested 5 foot gauge might be theoretically better. But it's questionable how much of an advantage it would be. A wider gauge would certainly provide more stability for heavy and high loads. But it probably wouldn't allow much more more traffic to be handled, as the things which constrain the amount of lading that can be carried by a rail car are mostly not gauge related. You could haul much more weight on a standard gauge railroad, but it would tear the railroad apart (that's why BNSF's Matt Rose has reportedly told his marketing people not to even consider 310,000 lb traffic). A wider guage wouldn't change that - the rails, ties, bridges, ballast and subgrade would still have to handle the same loadings.
But this is all academic. The factors that led to the demise of odd gauges on the US rail system over a century ago are still at work today. Even if a wider gauge had some advantages, the disadvantages of not being able to operate as part of the national rail network would dwarf them.
As a historical footnote, there were wider gauges than the Erie's 6 foot gauge. The Great Western Railroad in England used 7 foot guage, and the "break of gauge" point where the GW met the rest of the British rail network (I think it was at Glouchester, which I probably spelled wrong) was a major headache until the GW was standard gauged. Adolph Hitler wanted to build 9 foot gauge railroads to connect his empire, but that idea died with the Third Reich
Considering everything I can think of, I would say that the optimum gage for today (at non-recession levels of business) would be something approaching six feet.
All gage factors of capacity and cost rise in an incredible / bewildering geometric progression, so it is not easy to get a handle on all of the tradeoffs. Perhaps only an increase to 5’-4” would yield the capacity increase needed to match today’s demands.
But, in any case, I think the present gage is technically obsolete. It’s just that we are stuck with it. The issue of gage is certainly something to think about in today’s rush to blanket the country with the dedicated track of HSR.
BucyrusConsidering everything I can think of, I would say that the optimum gage for today (at non-recession levels of business) would be something approaching six feet. All gage factors of capacity and cost rise in an incredible / bewildering geometric progression, so it is not easy to get a handle on all of the tradeoffs. Perhaps only an increase to 5’-4” would yield the capacity increase needed to match today’s demands. But, in any case, I think the present gage is technically obsolete. It’s just that we are stuck with it. The issue of gage is certainly something to think about in today’s rush to blanket the country with the dedicated track of HSR.
Seriously, a wider gauge would lower the center of gravity of a HSR train, right? And, this could possibly improve performance of said train. However, that would cause the HSR equipment to be noninterchangeable with the current infrastructure. This would mean, to me, the dedicated lines of HSR will have a hard time being built in to major cities such as Chicago.
James
The HSR track will be built totally from scratch and be dedicated only to HSR. There need not be any interchangeability with the current standard gage system. Thus it becomes a whole new world of gage selection for HSR.
The ButlerAre you saying Americans are heavier today so we need to increase the gauge of HSR to compensate? Seriously, a wider gauge would lower the center of gravity of a HSR train, right? And, this could possibly improve performance of said train. However, that would cause the HSR equipment to be noninterchangeable with the current infrastructure. This would mean, to me, the dedicated lines of HSR will have a hard time being built in to major cities such as Chicago.
How would a wider gauge lower the center of gravity? Unless your planning on doing something like the Talgo, and doing without an axle, the axle can not intrude into the passenger compartment. And then people need to be able to stand within the vehicle.
Current width trackage is capable of resisting more overturning force than the passengers would be willing to withstand, tilting is done solely for passenger comfort, not to keep the train from rolling over. A wider gauge would do nothing to mitigate the forces acting on the passengers.
beaulieuThe ButlerAre you saying Americans are heavier today so we need to increase the gauge of HSR to compensate? Seriously, a wider gauge would lower the center of gravity of a HSR train, right? And, this could possibly improve performance of said train. However, that would cause the HSR equipment to be noninterchangeable with the current infrastructure. This would mean, to me, the dedicated lines of HSR will have a hard time being built in to major cities such as Chicago. How would a wider gauge lower the center of gravity? Unless your planning on doing something like the Talgo, and doing without an axle, the axle can not intrude into the passenger compartment. And then people need to be able to stand within the vehicle. Current width trackage is capable of resisting more overturning force than the passengers would be willing to withstand, tilting is done solely for passenger comfort, not to keep the train from rolling over. A wider gauge would do nothing to mitigate the forces acting on the passengers.
Increasing the gauge might conceivably increase passenger capacity, but not by a huge amount, unless you went up as well as out. This, of course, would raise clearance problems with the existing plant.
I think this comes under the "if we knew then what we know now" department. Of course, if that was the case, a lot of railroads we know and love might not have been built, either...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Falcon48(I think it was at Glouchester, which I probably spelled wrong)
Yes, Gloucester (pronounced with two syllables) is usually spelled without the letter "h." English names can trip us up when we attempt to spell them out. I notice that you go back and forth between "guage" and "gauge;" "gauge" has been the accepted spelling. I think, "goo-age" when I see "guage" but "Oua," as in "Ouachita," is pronounced "Wah."
On the whole, I appreciate your post.
I remember the article in Trains, several years back, about what might have been had Adolf Hitler's railroad been built.
Johnny
Falcon48 [snip] . . . A wider gauge would certainly provide more stability for heavy and high loads. But it probably wouldn't allow much more more traffic to be handled, as the things which constrain the amount of lading that can be carried by a rail car are mostly not gauge related. You could haul much more weight on a standard gauge railroad, but it would tear the railroad apart (that's why BNSF's Matt Rose has reportedly told his marketing people not to even consider 310,000 lb traffic). A wider guage wouldn't change that - the rails, ties, bridges, ballast and subgrade would still have to handle the same loadings. . . . [snip; emphasis added - PDN]
Amazing - somebody's using sound judgment. In particular, the increases in the wheel/ rail contact stresses, and their disproportionately negative effect on the fatigue life of the rail head - 'shelling' - is a principle disincentive.
'Guage' is a little archaic, but still accepted in the legal and financial communities - it's almost required in the latter - been used that way for a few centuries there, and so they're reluctant to change, is my understanding.
We had a heckuva thread on this same topic about 6 months or so ago, at the time of the Narrow-Gauge special Trains magazine issue. Would be worthwhile looking for and finding that one . . .
- Paul North.
Is this the one?
http://cs.trains.com/trccs/forums/p/131049/1474747.aspx#1474747
There are two aspects to the definition of optimum gage:
1) Hauling capacity.
2) Standardization of manufactured components of track and rolling stock.
If you include both items #1 and #2, then 4’-8 ½” is clearly the optimum gage overwhelmingly because of item #2.
However, I think the original poster was posing this question:
What is the optimum gage in terms of hauling capacity only?
I believe this question has never been answered, and that the answer has changed as railroads have evolved. During that evolution, traffic has grown, and so has the optimum gage as a consequence.
When 4’-8 ½” was adopted as standard, it was probably a little larger than optimum just based on the anticipation of traffic growth. Today, it may be optimum or a little less than optimum.
It would take an enormous effort of number crunching, and engineering and economic analysis to discover the optimum gage for today. I know of no such effort. No such effort is needed because the choice of gage today is guided by both items #1 and #2 above, and item #2 makes 4’-8 ½” the winner by a long shot.
However, if the perfect gage were sought today in terms of #1 alone, there is only the tiniest, most infinitesimal chance that it would be found to be 4’-8 ½”. If I were to bet, I would say that it would be found somewhere between 4’-8 ½” and six feet.
Kevin C. Smith Is this the one? http://cs.trains.com/trccs/forums/p/131049/1474747.aspx#1474747
Sorry - no, that's the Track Gauge & Loading Gauge thread from June and July 2008. It's not the one I had in mind - aside from the time frame, it's only 1 page and 8 items, and a pretty civilized discussion throughout.
I'll see if I can find it later on this morning or at lunchtime.
EDIT: I think this is it -
http://cs.trains.com/trccs/forums/p/159344/1756212.aspx#1756212
The subject also showed up a little bit in this thread from about the same time -
http://cs.trains.com/trccs/forums/t/158289.aspx?PageIndex=3
What's really scary - to me, anyway - is that they're all from 6 months ago, just like I said . . .
Bucyrus The HSR track will be built totally from scratch and be dedicated only to HSR. There need not be any interchangeability with the current standard gage system. Thus it becomes a whole new world of gage selection for HSR.
Back in the sixties GATX (yep, the freight car lessor) were promoting an 18 foot (!) gauge HSR system called RRollway, the idea being that automobiles could be driven straight on and off the train garage style (i.e at a right angle):
http://books.google.com/books?id=mikDAAAAMBAJ&pg=PA92&dq=rrollway&as_brr=1&cd=1#v=onepage&q=rrollway&f=false
However, I note that most existing HSR systems run on good 'ole 4'8'' and a half so why reinvent the (flanged) wheel...after all broad gauge increases ROW costs and a wider vehicle needs more juice (air resistance) to push it up to 225 M.P.H...
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
A new gauge for HSR would be practicable if you could afford new rights-of-way in built-up urban areas, similar to what was done in Japan. The French seem to have a more realistic approach in that the TGV has a separate right-of-way outside the cities but uses existing trackage in urban terminal areas.
The only advantage of a 6' wider guage might be the rolling stock could be much wider allowing more space inside any car especially passenger cars (could make for some nice sleeping rooms). Wider bulk cars would call for shorter cars for same axel loadings (would require less steel for the whole car).. That might make iron ore cars too short? That requires bridge loadings to be stronger. Also moving wide loads that could be wider ( 2-4 ft). A wider guage would also decrease the tendency of stringlining a train on the inside of a curve. A wider guage would call for curves not to be as tight because of wheel creep and requiring loco trucks to be more curve adaptable?
There would be no advantage for passenger train speeds on curves since the same amount of cant for a given speed and cant deficiency would be the same.
The cost of RR ties and ballast would be much greater because of the need for them to cover the wider track bed. ROW cleariing costs would be greater.
Falcon48 an increase in gauge would bean that bridges and such would have increased loads. Wider bridges would certainly weigh more and they have to support their own weight first. In addition everthing would cost more with no return on that investment.
Deggesty Falcon48(I think it was at Glouchester, which I probably spelled wrong) Yes, Gloucester (pronounced with two syllables) is usually spelled without the letter "h." English names can trip us up when we attempt to spell them out. I notice that you go back and forth between "guage" and "gauge;" "gauge" has been the accepted spelling. I think, "goo-age" when I see "guage" but "Oua," as in "Ouachita," is pronounced "Wah." On the whole, I appreciate your post. I remember the article in Trains, several years back, about what might have been had Adolf Hitler's railroad been built.
We have discussed this subject in several threads in the past, and each time, there is a consensus that the present gage of 4’-8 ½” is perfect and should not be changed. But the original poster of this thread was not asking if we should change today’s standard gage to a better gage. That would be impossible. There cannot possibly be an alternate gage that would offer enough of an advantage to change all of the physical plant we have today.
What the original poster was asking is this: Has there ever been an engineering / economic study to determine with certainty what the optimum gage would be if we were starting from scratch and had no prior commitment to 4’-8 ½”?
I speculate that the answer to that question is no. And I would also speculate that 4’-8 ½” is not the optimum gage today in the terms of the original poster’s question. The odds of that would be impossibly remote.
Any gauge in the range of 4'6" to 5'0" would be just fine based on our emprical knowledge. Narrower would begin to suboptimize from a perspective of unit sizes of the human body and its effects on the practical sizes of motor vehicles, equipment, tools, roadways, buildings, etc. Wider would begin to suboptimize on the limits of metallurgical properties. People have had plenty of opportunity in the last 100 years to try on radically different gauges and no practical person has seen any need to.
Any engineering study to determine "ideal gauge, history notwithstanding" for a start-from-scratch-world would require dozens of assumptions any one of which has so much range of potential magnitude that you would never be able to come to a more precise answer than 4-6" to 5'0". Why waste time and money seeking precision when there is no precision to be had?
The lack of engineering studies ought to be your indication that none is needed -- it's like asking, "would the world be a better place if the sky was a 10% lighter or darker shade of blue?"
RWM
RWM,
I agree that there is no practical reason to look for an alternate gage, and so no engineering studies are needed to search for that alternate gage. All I am saying is that today, with sophisticated computer programs, we could run the numbers and seek the answer to the question of optimum gage with far more precision than what was available when gage was standardized. However, as you mention, the input would be enormously complex, and the answer to the question would probably be disputed. The way I see it, the question is only academic, but highly intriguing nevertheless.
I would say that the answer to the original poster’s question is: We will never know.
Computers and software do not help you with this type of inquiry, they only hurt you. They imply precision and accuracy where none actually exist. Computer models are very helpful at adding up lots of numbers and running a lot of calculations quickly, for relationships that are established, prioritized, and categorized by humans. Computer "black box decision capabilities" where you input a bunch of what-if questions and desired results, and the computer spits out an answer like "build your railroad to a gauge of 4'8.000001" only exist in movies. For example, we use a computer tool called "Rail Traffic Controller" to mimic actual train operation over an actual infrastructure to validate infrastructure capacity and rail operations questions. People are very impressed when they see the RTC simulation running because it shows lots of little scale trains running around a scale infrastructure like it's all magic. In reality, the RTC model is nothing more than a big Excel spreadsheet. I could do everything it does with pencil and paper, it would just take me time. And -- more important -- all it does is test a scenario a human proposes. It doesn't dream up new or better scenarios! You run a scenario, decide if you can live with the outcome, and if you don't like the outcome you change variables -- one at a time -- and rerun to see if when you change a variable you like the outcome any better.
I think I would prefer the answer, "So long as you're in the 4'6" to 5'" range, It does not matter."
Railway Man ..."build your railroad to a gauge of 4'8.000001" ... I think I would prefer the answer, "So long as you're in the 4'6" to 5'" range, It does not matter."
..."build your railroad to a gauge of 4'8.000001" ...
In most cases, the "figure of merit" versus some parameter function has a broadly rounded peak versus a sharp well defined peak and I would be very surprised if the "figure of merit" versus gauge function had a sharp peak. IOW, the exact optimum doesn't matter.
Debating optimum gauge is a bit like debating optimum optimum frequency for electric power systems - 50 and 60 Hz are close enough to the optimum (read best compromise) that it doesn't make sense to change from one to another unless it is to become part of a larger grid (e.g So Cal Edison changing from 50 to 60 Hz in 1947-48).
Railway ManWider would begin to suboptimize on the limits of metallurgical properties.
Wider would begin to suboptimize on the limits of metallurgical properties.
Sounds like metal fatigue in axles. Speaking of axles, unpsrung weight would likely increase with gauge.
Another problem is wider gauges increase curve resistance
I'm pretty sure that there were some engineering studies done by BART in the early 60's, the 5'6" gauge was selected to allow operation over the Golden Gate Bridge. Of course this was for a different problem than a general purpose railway.
- Erik
I am not sure I understand the objective of increasing the gauge.
Is it to increase overall capacity per unit length of train/track?
Is it to make cars shorter for the same capacity in order to reduce train length?
Is it to reduce tare weight?
Is it to carry items that they presently cannot carry?
Assuming there are no engineering issues associated with increasing the gauge, what would improve by doing so?
Anthony V.
erikemRailway ManWider would begin to suboptimize on the limits of metallurgical properties.Sounds like metal fatigue in axles. Speaking of axles, unpsrung weight would likely increase with gauge.- Erik
Rolling contact fatigue on the rail head is the present economic limit. You can solve that problem with either more rails or more wheels (think three-axle bogies, or articulated cars with less carbody/lading per bogie), but those introduce new and worse economic problems. The Pilbara heavy-haul lines have pushed average axle loadings higher than anyone in the world but that has been possible only because they are a closed and closely controlled system with intensive monitoring and fine-grained adjustment of rail profile, wheel profile, rail-head lubrication, locomotive tractive effort parameters, line and surface, etc.
Railway ManComputers and software do not help you with this type of inquiry, they only hurt you. They imply precision and accuracy where none actually exist.
Computers and software do not help you with this type of inquiry, they only hurt you. They imply precision and accuracy where none actually exist.
Like the old saying: "Garbage in. Gospel out."
There are a number foreign rail systems operating on wider gauge track. Most of the lines in Spain and Portugal are 1668 mm (5' 5 2/3"), but Spain's high speed passenger lines are on 4' 8 1/2" track as that the standard for similar purposed lines in the most of the rest of Europe.
It seems that someone with time, money, fluency in Spanish and no particular goal in life could probably dig down through the minutiae of Spain's ADIF (the rail infrastructure company) construction and maintenance costs and answer the questions posed by this thread. Useful? The answer "43" comes to mind.
An aside, Spain has passenger trains that run over both gauges and have several facilities to change the gauge on the cars. The operation takes about 15 minutes with most of the time spent cutting off the engine of one gauge and coupling on the engine of the other gauge after the cars have been run through the facilitiy. Here is how they do it. http://www.talgoamerica.com/pdf/Talgo-RD-System-Brochure.pdf
"We have met the enemy and he is us." Pogo Possum "We have met the anemone... and he is Russ." Bucky Katt "Prediction is very difficult, especially if it's about the future." Niels Bohr, Nobel laureate in physics
jeatonThere are a number foreign rail systems operating on wider gauge track. Most of the lines in Spain and Portugal are 1668 mm (5' 5 2/3"), but Spain's high speed passenger lines are on 4' 8 1/2" track as that the standard for similar purposed lines in the most of the rest of Europe.
Do these systems use rolling stock that is larger than those operating with standard gauge?
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