fredswain wrote:According even to the links I provided, wheel diameter is a factor when determining TE. Am I reading something wrong?
Could be a factor, depending on what info you're starting with. If you somehow know the motor's torque and gear ratio, you'll naturally need to know driver diameter to calculate the TE-- and you could calculate rail horsepower from that TE if you wanted. But if you're starting with the rail horsepower and locomotive speed, then driver diameter is irrelevant.
Same with a steam locomotive. If you somehow know the MEP of the steam in the cylinder, and the cylinder diameter and stroke, then you need the driver diameter in order to calculate TE. But if somebody gives you the rail horsepower at a given locomotive speed, then you know the engines TE at that speed-- whatever its dimensions.
feltonhill wrote:Timz has a point here. 7,500 tons at 64 mph on level track would take 10,000 to 11,000 drawbar hp, steam, diesel, electric or millions of mice. An A can't to it on level track. Such speed would require about a -0.15% downgrade with a single A. Davis formulas aren't perfect, but they're very good at estimating train resistance. Timz has a working knowledge of this info - he's done the homework, years ago.
Hi Feltonhill and Timz,
the U.P track from Julesburg to North Platte is ~ -0.15%. Reaching speeds with 7657tons up to 50, 60-70mph with 3985 should be plausible, now.
Can we calculate the DBHP by that?
Kind regards
Lars
Lars Loco wrote:With the arrival of the EMD- and GE- 6000HP engines, the rail-industry finally could replace the big articulates on a per unit calculation...40 years later ;-)
With the arrival of the EMD- and GE- 6000HP engines, the rail-industry finally could replace the big articulates on a per unit calculation...40 years later ;-)
Supposedly the rationale for the UP's Big Blows was to replace the Big Boys on a one-for-one basis. The DDA-40X's were then supposed to replace the Big Blows on a one for one basis.
OTOH, the Milwaukee's Little Joe's were about the equivalent of an articulated steamer at low speeds, but power dropped off above 30 MPH (series motors from a constant voltage supply).
MichaelSol wrote: Bucyrus wrote: fredswain wrote: There may have been no animosity meant. For some reason it just rubbed me wrong. No harm done. We're all friends here.According even to the links I provided, wheel diameter is a factor when determining TE. Am I reading something wrong?It appears to me that you could arrive at TE by two different routes. One would be by the formula using rail horsepower and speed. The other would be by the formulas using the thrust force of steam or the torque force of the traction motor. In the first method, wheel diameter does not play a role, but in the second method, it does. With the second method, you would not need to know the rail horsepower or any other measure of horsepower.A third way is to rely on the power curves produced by a dynamometer car which removes any doubt that may exist as to the usefulness of one theory of calculation or the other and, as well, provides instant visual access to actual measured locomotive performance across the performance range.
Bucyrus wrote: fredswain wrote: There may have been no animosity meant. For some reason it just rubbed me wrong. No harm done. We're all friends here.According even to the links I provided, wheel diameter is a factor when determining TE. Am I reading something wrong?It appears to me that you could arrive at TE by two different routes. One would be by the formula using rail horsepower and speed. The other would be by the formulas using the thrust force of steam or the torque force of the traction motor. In the first method, wheel diameter does not play a role, but in the second method, it does. With the second method, you would not need to know the rail horsepower or any other measure of horsepower.
fredswain wrote: There may have been no animosity meant. For some reason it just rubbed me wrong. No harm done. We're all friends here.According even to the links I provided, wheel diameter is a factor when determining TE. Am I reading something wrong?
There may have been no animosity meant. For some reason it just rubbed me wrong. No harm done. We're all friends here.
According even to the links I provided, wheel diameter is a factor when determining TE. Am I reading something wrong?
It appears to me that you could arrive at TE by two different routes. One would be by the formula using rail horsepower and speed. The other would be by the formulas using the thrust force of steam or the torque force of the traction motor. In the first method, wheel diameter does not play a role, but in the second method, it does. With the second method, you would not need to know the rail horsepower or any other measure of horsepower.
A third way is to rely on the power curves produced by a dynamometer car which removes any doubt that may exist as to the usefulness of one theory of calculation or the other and, as well, provides instant visual access to actual measured locomotive performance across the performance range.
Within the precision and accuracy of the measurement device and provided that proper calibration was done before and after each test run.
A quote I read long ago: "Nobody questions the data except the engineer who gather it. Everybody questions the analysis except the engineer who performed it"
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
fredswain wrote: timz wrote:...if two locomotives have the same rail horsepower at the same speed they have the same TE, by definition.Not true.
timz wrote:...if two locomotives have the same rail horsepower at the same speed they have the same TE, by definition.
Not true.
fredswain wrote:...would someone please in a nice way other than to say "since it's going to be wrong", please tell me in a mature manner why or where I went wrong?
You (perhaps reasonably) felt insulted by that clause, but it was as if I had said 31 x 31 = 961 and you had denied it. Naturally (knowing I was right) I asked you to show your calculation-- but warned you it was bound to be wrong and so would be wasted effort.
Thing is, rail horsepower is defined as TE (in pounds) times speed (in miles/hour) divided by 375. Many or most fans seem to think horsepower has some kind of existence independent of TE (as in some of the quotes at the beginning of this thread) -- but it doesn't. At 37.5 mph, rail horsepower is always exactly a tenth of the TE in pounds; at 3.75 mph it's a hundredth, and similarly at whatever other speed.
If two locomotives have the same tractive effort (TE) at the same speed (V) then the rail horsepower for the first one is (TE x V)/375 and for the second one is the same. As you see, there's no place for driver diameter or torque or adhesion or anything else to shoehorn its way into the calculation. (TE depends on adhesion, of course, but if slippery rails cut TE in half they cut the rail horsepower in half too.)
fredswain wrote: OK I found these on Wikipedia. I wish I'd have checked there earlier. I was in fact going in the right direction with my math and what I had was correct from a formula standpoint. I just hadn't gotten all of the information yet which means the answer would still be wrong. Not too shabby for just thinking things through though. It was hardly a waste of time as I'm sure some people think studying is.http://en.wikipedia.org/wiki/Tractive_effort#Related_statisticshttp://en.wikipedia.org/wiki/Factor_of_adhesion
OK I found these on Wikipedia. I wish I'd have checked there earlier. I was in fact going in the right direction with my math and what I had was correct from a formula standpoint. I just hadn't gotten all of the information yet which means the answer would still be wrong. Not too shabby for just thinking things through though. It was hardly a waste of time as I'm sure some people think studying is.
http://en.wikipedia.org/wiki/Tractive_effort#Related_statistics
http://en.wikipedia.org/wiki/Factor_of_adhesion
Stick to your guns. You are doing just fine.
Feltonhill wrote:
" If Archer Hill was only a 0.07% grade, then 30 mph may be possible with 3985 "
No, it is 0.7%. But the train must really have gained momentum at that point... and probably not the whole consist was on the grade. It is just a short grade, but it would be funny to read a dynometers cars's plot there.
Do we really need 10000-11K diesel HP to pull such a consist? At a chart of a GE AC6000 loco, it shows 7736 trailing tons @ 55mph on level track, a quite similar output to #3985. The downgrade and the lower train resistance of the unit train would probably help to perform this stunt, too.
But it shows clearly, where the advantages of high drivered articulates are: max. HP at speeds around 30mph - 50mph.
A steamlocomotive at speeds do not has to be more powerful than a comperable diesel-engine automatically.
Have a look at the N&W:
Though the 5600HP Y6b with 58inch drivers has a higher peak HP than the A, it reaches its max. HP at 25mph, and then falls quickly. Then the 5300HP Class A with 70inch drivers intercepts Y6b's traffic effort curve at 30mph. Here the Class A just comes into its power curve and stays above 5000HP until 70mph with a TE at round about 28.000lbs at that speed. The Y6b produces this output at around 45mph. But we need 2 kinds of steamengines, to displace one kind of diesel-engine (a 6000HP one).
Interestingly, though, the chart shows a maximum output of ~5300HP for the A, some claimed it had 6300DBHP.
This makes me wondering, that there were big variences about steam-engines output, see also the Ally's claimed 7500DBHP, where in general service its output was ~6500DBHP.
Nevertheless, the output of steam and diesel engines appears so different at the engines speed ranges, a fair comparison would be as following: Calculating the area size under the TE-curve, as bigger, as better.
Fun intended:
JayPotter wrote: MichaelSol wrote:I doubt that H.F. Brown and R.P. Johnson really needed to have any stories read to them to understand Steam locomotion, and I think that is somewhat demeaning to suggest that they relied on narrative instead of quantitative analysis since the contrary is plainly true, and it appears to me that you have it backwards.Michael, if you'll please take another look at what I wrote, I think you'll see that I made no suggestion, demeaning or otherwise, about Brown or Johnson. I was referring to the people in this group who are, in your view, challenging Brown and/or Johnson.
MichaelSol wrote:I doubt that H.F. Brown and R.P. Johnson really needed to have any stories read to them to understand Steam locomotion, and I think that is somewhat demeaning to suggest that they relied on narrative instead of quantitative analysis since the contrary is plainly true, and it appears to me that you have it backwards.
Michael, if you'll please take another look at what I wrote, I think you'll see that I made no suggestion, demeaning or otherwise, about Brown or Johnson. I was referring to the people in this group who are, in your view, challenging Brown and/or Johnson.
I understood it, but perhaps did not phrase what I am seeing well. There are well developed studies by experienced motive power engineers dealing entirely with the quantitative record developed for Steam power. That is what they are all about.
There are people here, however, interested in purely hypothetical outputs of equations of which the understanding is both incomplete and perhaps even inaccurate. And when the authentic studies don't support their entirely theoretical conclusions, it must be because the studies are wrong, rather than their incomplete understanding the question.
Aside from the arrogance factor, which both Fred and I find offensive, on issues of credibility I just can't suggest that H.F. Brown and R.B. Johnson had an incomplete understanding of the question simply because these gentlemen say so, and certainly not because anything that these gentlemen have said thus far -- including the fact that none of them offered the same objection to the same data as recently as two years ago -- suggests that they have either the background or experience on the subject matter to offer an opinion, let alone an informed one.
JayPotter wrote: MichaelSol wrote: That record is now being challenged by people who, frankly, I don't think deserve to sharpen the pencils of those engineers from the standpoint of training, education and most of all: long, actual, daily experience with the motive power types in question -- both kinds.Since I know nothing about the training or education of these people, I may be wrong; but my impression is that the record -- or whatever is being challenged -- is being challenged primarily by people who prefer to receive information about quantitative issues in quantitative -- as opposed to narrative -- form.
MichaelSol wrote: That record is now being challenged by people who, frankly, I don't think deserve to sharpen the pencils of those engineers from the standpoint of training, education and most of all: long, actual, daily experience with the motive power types in question -- both kinds.
That record is now being challenged by people who, frankly, I don't think deserve to sharpen the pencils of those engineers from the standpoint of training, education and most of all: long, actual, daily experience with the motive power types in question -- both kinds.
Since I know nothing about the training or education of these people, I may be wrong; but my impression is that the record -- or whatever is being challenged -- is being challenged primarily by people who prefer to receive information about quantitative issues in quantitative -- as opposed to narrative -- form.
I doubt that H.F. Brown and R.P. Johnson really needed to have any stories read to them to understand Steam locomotion, and I think that is somewhat demeaning to suggest that they relied on narrative instead of quantitative analysis since the contrary is plainly true, and it appears to me that you have it backwards: the gentlemen here are relying on theoretical results of partially understood equations, not actual quantitative measurements as summarized in the published studies during the period that the equations in question were derived.
I think Brown, Johnson, et.al. had a better grip on the quantitative aspects of the argument because they had not only a better understanding from the perspective of long and actual experience as motive power specialists -- which none of these people have regarding Steam -- but ready access to the practical quantitative data underlying their observations -- which the gentlemen here acknowledge they do not have.
And I think the weight of the quantitative nature of the argument goes in favor of those who actually had the quantitative data to review -- whether represented in published form graphically or otherwise -- as opposed to the admittedly theoretical interchange here of equations, not actual data. And if you and I disagree on that, let me make it clear: I favor the studies -- actual studies -- that have been done and which examine the quantitative data underlying the conclusions of those studies, including the graphical representations of the quantitative data. What you are seeing on this thread is not a respect for quantitative data, but something entirely different: "my partially misunderstood and incomplete equation is better than your partially misunderstood and incomplete equation."
And if the quantified data as represented by thoroughly experienced engineers does not conform to the partially misunderstood equations bandied about here -- well the data must be wrong? Right?
Indeed, if you refer to the earlier comment "If you want to believe 60 year old studies ..." I think you see the context that weakens any claim that these guys are looking to legitimate quantitative support, since any objective source would recognize that, regarding Steam, the good data would have been developed ... just about 60 years ago ... Well, if you're not interested in the data and studies from the time period they would have been authentically produced -- you must be interested in something else. And I think he is.
If there is a benefit of the doubt here, it has to go to Brown, Johnson, and the recognized experts of the era in question, and not the least so because they not only actually had the quantitative data, and crucial experience with that data, and were acknowledged authorities on motive power, but also because of the peer reviewed nature of their works by virtually every other knowledgeable, recognized authority on the matter.
And I don't think that the "benefit of the doubt" in this case has much doubt to overcome on that score ... notwithstanding their own opinions of themselves, none of the gentlemen here is a recognized authority.
Indeed, when you use the word "narrative" I see it differently. There is a "narrative" about Steam vs. the Diesel-electric; one based far more on emotion than one would expect, which is why people continue to make these goofy posts that "water" is an insurmountable problem for Steam, but that fuel and lubricants are not a similar or in reality far greater "problem" from a cost standpoint for the Diesel-electric.
The Steam studies don't fit "the narrative". And it is all about "the Narrative" and that is really what this thread is now about.
Hi Feltonhill, have many thanx for your reply!
Do you have this video, too?
It was true.
To get more confused, the whole consist ran up Archer on the west-side, a 0,7% grade and topped the hill with 30mph!
How it did that? Probably it came down a similar grade and accelerated to overcome this grade.
BTW, the train was 8900ft long and contained 143 cars. I will send you the exact weight, when I arrive home, but it was more than 7500t!
I have no doubt, that this was possible. Basically, the Cheyenne-Nebraska-run was downhill, but still a show...
Last time I checked, 7,500 tons at 60 mph on level track would take 10,000-11,000 DBHP. 3985 ain't got that much and neither does/did 1218. I've looked at the video of 3985 numerous times on Archer hill and elsewhere, and I'm very suspicious that the stack train didn't weight anywhere close to 7,500 tons. Can anyone confirm? There's something wrong here.
And 3985 is a perfectly fine 5,000 DBHP loco, but much more than that any you're probably going down a bit too far the boiler efficiency curve for economical/sustained operation.
The increased variability of the H-8's DBHP readings as speed increases reflect the effect of variable road conditions. For example, C&O did not correct dyno car readings for acceleration, so if the speed was not constant when the individual readings at a milepost were taken, the figure may be either under or over-stated, although probably not by much.
Hello everybody,
what about considerations, that a steamer has great variances about HP-output, es. at higher (+40mph) speeds? An engine, that was put in service as a 5000HP one, could produce, under feasible circumstances, say 6000HP, couldn't it?
Look at the 1990ties Challenger APL-run:
It took a 28 5-unit stack-train from Cheyenne down to Nebraska. Consist weighted 7500tons, max. speeds were 60-70mph (on level track as well, listen H. Fogg's comment and look how fast the trains passed the grain-towers near Chappell, Nebr.).
Was this a 5000HP engine, as the Challenger-Class was suppossed to be, or did it 6000HP?
Furthermore, see the jitters at the Ally's drawbar-test at higher speeds!
JayPotter wrote: There are fewer dissertations on theoretical locomotive performance than there used to be. One reason for this is that the industry discovered that theoretical performance oftentimes does not match actual performance. In other words, it's not unusual for a locomotive model not to perform in actual service the way that the manufacturer expected it to perform. So some past theoretical predictions of future performance have turned out to be inaccurate; and those of us who want "reliable" current theoretical analyses -- peer-reviewed or otherwise --might be searching for something that doesn't exist.There are also relatively few dissertations on the actual performance of locomotives.
There are fewer dissertations on theoretical locomotive performance than there used to be. One reason for this is that the industry discovered that theoretical performance oftentimes does not match actual performance. In other words, it's not unusual for a locomotive model not to perform in actual service the way that the manufacturer expected it to perform. So some past theoretical predictions of future performance have turned out to be inaccurate; and those of us who want "reliable" current theoretical analyses -- peer-reviewed or otherwise --might be searching for something that doesn't exist.
There are also relatively few dissertations on the actual performance of locomotives.
And none for Steam? I am referring, though, to a generation of experienced mechanical engineers who had done thousands of dynamometer tests -- nothing theoretical about that -- with both Steam and Diesel-electric. A great deal of interest, energy and expertise was specifically applied to the question at the time, not only because of the great stakes involved for the industry as a whole, but for the success or failure of a variety of manufacturers on both sides of the question.
And that goes to the strength of the "peer" review process then, as opposed to now, because each "side" of the debate, with so very much at stake, had every reason to point out the failures, fallacies and misrepresentations of the alternative, and to emphasize the strength of their own.
To the extent that the most knowledgeable people in that debate are gone, they have left behind a well-documented record of that debate and those comparisons.
Nothing theoretical about a dynamometer car test. One of the gentlemen here claims, on top of his knowledge, to be frustrated by a lack of test information from the era. Well, while the handicap may indeed be fatal to understanding the motive power type today; it was not for the lack of tens of thousands of such tests over the widest range of conditions that the industry had a good understanding then, as reflected in solid publications from the era.
These graphs have been used here before. The same gentlemen had nothing to say about them then. But the nature of the debate doesn't change. It's always the same pattern: "show just one ..." , and when you do, it's "oh yeah, well show just two ....", and then finally it's multiple publications, many references spanning 40 years and it just ends up with the baloney posted above -- something to the effect of well that was a long time ago and "if you want to believe 60 year old studies complete with graph errors, go ahead, it is a free country" even though it was an "obvious error" he had not "noticed" during previous incarnations of the same discussions.
Is he getting smarter since he last missed the error? Has he learned something new about Steam since then? Or is it simply the latest in a series of offensive tactics by an individual who generally smears anyone he disagrees with, in any way he can; most recently as toadies of the coal industry? And I get the sense this episode qualifies; it's not whether he even understands it or not, then or now, its simply part of the offensive, right or wrong.
As I have thoroughly pointed out, notwithstanding the prominence of the graph in multiple publications -- and apparently the graph has in fact, been re-plotted at least once to incorporate different data -- and the significance of its findings, four generations of motive power engineers representing all sides of the debate could not, in their published comments on the matter, find the "error." In this instance, the Brown paper, the graph simply could not have gotten a wider circulation nor a more diverse published commentary from knowledgeable motive power engineers including GM's best people.
And, if practical confirmation counts, the graph fits with what the men who ran the engines testified to at the time; and the record is replete with their accounts that the Steam power would "run away" and leave the Diesel-electrics in the dust at the higher speeds. The fact is, the experience of locomotive engineers and the studies of the motive power engineers support the Brown paper, but can only leave a neutral reader perplexed that the arguments offered on this thread cannot account for -- indeed are contrary to -- the testimonials of the men who were, once again, actually there.
It's been an interesting thread, but when the argument finally gets down to a loud few denouncing and denigrating a generation of recognized motive power engineers who did, in fact, have the actual experience and took the time to generate authoritative books and papers, I am going to defer to the experience and knowledge of the folks who "were there" and were recognized by the broadest engineering community of knowing what they were talking about; and this bunch here doesn't qualify.
I think there is some historical revisionism going on here, and when done simply to compel a "win" in an argument, without the credentials or experience to write, for instance, a peer reviewed article in a professional journal, I am going to call the baloney for what it is, recognize that there is an authentic record by legitimate authors on the topic, refer to them for actual facts on the matter, and call it a day.
timz wrote: Bucyrus wrote:I thought the whole point of a comparison was to prove something rather than to just leave the conclusion to the eye of the beholder.If you mean "get your opponent to admit you're right", no use hoping for that.
Bucyrus wrote:I thought the whole point of a comparison was to prove something rather than to just leave the conclusion to the eye of the beholder.
If you mean "get your opponent to admit you're right", no use hoping for that.
I see what you mean.
fredswain wrote:I'd rather have someone make themselves useful and show me the PROPER way to figure things out.
I don't think it's a matter of being proper or improper; but you might try approaching tractive effort on a per-axle basis. In other words, the TE of a locomotive is the sum of the TE produced by each of its powered axles. Taking this axle-by-axle approach to TE might make it easier for you to deal with adhesion issues, because all wheels on a locomotive do not necessarily have the same factor of adhesion at any given time.
MichaelSol wrote:Well, if anyone else thinks there is something weird here, with multiple professional publications by recognized authorities being denounced as just being plain wrong, by people who cannot offer their credentials, and these guys "PM-ing" each other with their secret handshakes and perfect knowledge, you're not the only one. There is something weird about this conversation, and because it isn't worth my time, for sure, I will stick with the published experts who are acknowledged authorities and will ignore, henceforth, the pseudo-authorities. And it isn't that they can't present a case; it's a matter of credibility that they haven't demontrated the peer-reviewed published credentials that others have.
There is something weird about this conversation, and because it isn't worth my time, for sure, I will stick with the published experts who are acknowledged authorities and will ignore, henceforth, the pseudo-authorities. And it isn't that they can't present a case; it's a matter of credibility that they haven't demontrated the peer-reviewed published credentials that others have.
I have some thoughts on the peer-reviewed-public-credentials issue.
There are also relatively few dissertations on the actual performance of locomotives. One reason for this is that records of actual performance are largely proprietary to the manufacturer, to the railroad, or to both. People who want to analyze the performance of a modern locomotive do not -- as those of us in Internet discussions often do -- churn around formulas and plot graphs. They merely download the contents of the unit's event recorder. So if GE wants to show CSXT that its AC6000CWs will produce 28,300 lbs of TE at 74 mph, all it has to do is refer to the TE value plotted by the event recorder of one that has accelerated a heavy train to 74 mph. And if CSXT wants to perform the railroading counterpart to a "peer-review" of this GE-produced data, it will perform a parallel measurement using its own instrumentation.
So to get back to the original issue, I really don't consider it "weird" if someone who I believe (based on my assessments of the data that they cite and the reasoning that they apply to that data) has recent first-hand knowledge of locomotive performance disagrees with theories advanced by, or conclusions drawn by, someone else at some point in the past, regardless of the latter person's "peer-reviewed public credentials". And I can understand why someone who works, or has worked, in the industry would be selective in the information that he or she offers for public consumption on the Internet.
timz wrote: Show us an example, plugging the numbers into the formula. Don't work too hard on it (since it's going to be wrong) but hopefully it won't take too long to straighten out this particular aspect of the problem.
Show us an example, plugging the numbers into the formula. Don't work too hard on it (since it's going to be wrong) but hopefully it won't take too long to straighten out this particular aspect of the problem.
Well if I in fact have been wrong about this, it would have been nice if someone had pointed that out EARLIER! I've made it clear that I've been learning as I go and I have shown my train of thought along the way. With no real help I might add. If something is wrong, kindly make yourself useful at ANY point and tell me and let me work on it. I don't pride myself on being wrong and like to fix it if there is a mistake somewhere. I also don't like to be insulted in the process. Correct me if I'm wrong but keep the attitude at home.
Saying that, I'll keep studying until I get it right. That's my ultimate goal. If I have missed anything else, would someone please in a nice way other than to say "since it's going to be wrong", please tell me in a mature manner why or where I went wrong? I'd rather have someone make themselves useful and show me the PROPER way to figure things out rather than to just flat out denounce the only examples shown.
GP40-2: Thank you for the info.
GP40-2 wrote:On my previous comments on CSX's AC6000s, they can produce 28,300 lbs of TE @ 74MPH. That's all I am going to say about them. Take it or leave it. I explained to Selector in a PM why I can't give more info.
GP40-2 wrote:Feltonhill,Please check your PM on this subject.
GP40-2 wrote:AnthonyV,Please check your PM concerning this subject.Thanks, GP40-2
AnthonyV,Please check your PM concerning this subject.Thanks, GP40-2
Well, if anyone else thinks there is something weird here, with multiple professional publications by recognized authorities being denounced as just being plain wrong, by people who cannot offer their credentials, and these guys "PM-ing" each other with their secret handshakes and perfect knowledge, you're not the only one.
There is something weird about this conversation, and because it isn't worth my time, for sure, I will stick with the published experts who are acknowledged authorities and will ignore, henceforth, the pseudo-authorities. And it isn't that they can't present a case; it's a matter of credibility that they haven't demontrated the peer-reviewed published credentials that others have. And when it gets down to these juvenile secret PMs and denunciations -- sorry, I will just withdraw and go with the honest, peer-reviewed, authorities.
And feel no worse in the morning by a choice that has often served well in the past.
fredswain wrote: timz wrote:...if two locomotives have the same rail horsepower at the same speed they have the same TE, by definition.Not true...
Not true...
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