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QUOTE: Originally posted by GP40-2 QUOTE: Originally posted by oltmannd QUOTE: Originally posted by feltonhill The grade from Portsmouth to Williamson on the N&W is descending westbound at about -0.016% for the first 100 miles (range - level to -0.058%), upgrade 0.30% at Kenova over the Ohio River and -0.012% for the last 30 miles or so into Portsmouth. Train weight varied depending on the mix of 50-ton and 70-ton cars. At a train length of 160 cars, trailing weight would be about 12,000 to 15,000 tons. Ultimately, a single A was expected to haul 180 cars over the division, a trailing weight of up to 17,000 tons. According to GP40-2's figures, a CW44AC could develop 4,305 DBHP. To match the A's performance, it would need between 5,300 and 5,400 DBHP, so it would not match a single A's performance overall. The GE's operating economy would obviously be much better. Again according to GP40-2's figures, a CW60AC would have about 5,895 DBHP. This is beyond the range of an A in daily service. I've found no data for an FEF-3 above 75 mph, so I don't know what it would do with any certainty. Existing information indicates that they were very capable performers in regular service and could reach their design speed (100-110mph) easily. However, they were not record-breakers in the DBHP department according to the small amount of test info available. Don't know why. GP40-2's figures for the P42 indicate that it would develop 3,850 DBHP at 100 mph. This would be pretty rarified atmosphere for steam and is likely well beyond the range of an FEF-3. My guess is that an FEF-3 would develop about 2,500 to maybe 2,700 DBHP at 100. Since I don't have access to much diesel information, I find the relatively high percentage of rated HP making it to drawbar HP unusual. I didn't think they were that efficient from prime mover to rear coupler. I think the diesel numbers being thrown around are net traction HP which is elec power out of the main gen headed for the traction motors. You'd have to factor in losses in the traction motor and gear set plus some allowance for HP to move the loco itself. My recollection is that the overall eff. from engine shaft into generator (traction HP) to drawbar is about 80%. Try in the neighborhood of 93% to 96% of the actual crankshaft horsepower for the latest designs. Even the orginal EMD FT's were 82% to 84% efficient, and that was with using unsophiscated DC generators/ DC traction motors. Nominal Horsepower rating is the minimum HP available to the alternator. This is a conservative number, and actual crankshaft HP into the alternator is usually several hundred HP higher than the Nominal rating. Currently I am not a liberty to discuss the latest tests on the new ES44DC's, but they have eye popping efficiency from crankshift to drawbar, especially for DC traction motors.
QUOTE: Originally posted by oltmannd QUOTE: Originally posted by feltonhill The grade from Portsmouth to Williamson on the N&W is descending westbound at about -0.016% for the first 100 miles (range - level to -0.058%), upgrade 0.30% at Kenova over the Ohio River and -0.012% for the last 30 miles or so into Portsmouth. Train weight varied depending on the mix of 50-ton and 70-ton cars. At a train length of 160 cars, trailing weight would be about 12,000 to 15,000 tons. Ultimately, a single A was expected to haul 180 cars over the division, a trailing weight of up to 17,000 tons. According to GP40-2's figures, a CW44AC could develop 4,305 DBHP. To match the A's performance, it would need between 5,300 and 5,400 DBHP, so it would not match a single A's performance overall. The GE's operating economy would obviously be much better. Again according to GP40-2's figures, a CW60AC would have about 5,895 DBHP. This is beyond the range of an A in daily service. I've found no data for an FEF-3 above 75 mph, so I don't know what it would do with any certainty. Existing information indicates that they were very capable performers in regular service and could reach their design speed (100-110mph) easily. However, they were not record-breakers in the DBHP department according to the small amount of test info available. Don't know why. GP40-2's figures for the P42 indicate that it would develop 3,850 DBHP at 100 mph. This would be pretty rarified atmosphere for steam and is likely well beyond the range of an FEF-3. My guess is that an FEF-3 would develop about 2,500 to maybe 2,700 DBHP at 100. Since I don't have access to much diesel information, I find the relatively high percentage of rated HP making it to drawbar HP unusual. I didn't think they were that efficient from prime mover to rear coupler. I think the diesel numbers being thrown around are net traction HP which is elec power out of the main gen headed for the traction motors. You'd have to factor in losses in the traction motor and gear set plus some allowance for HP to move the loco itself. My recollection is that the overall eff. from engine shaft into generator (traction HP) to drawbar is about 80%.
QUOTE: Originally posted by feltonhill The grade from Portsmouth to Williamson on the N&W is descending westbound at about -0.016% for the first 100 miles (range - level to -0.058%), upgrade 0.30% at Kenova over the Ohio River and -0.012% for the last 30 miles or so into Portsmouth. Train weight varied depending on the mix of 50-ton and 70-ton cars. At a train length of 160 cars, trailing weight would be about 12,000 to 15,000 tons. Ultimately, a single A was expected to haul 180 cars over the division, a trailing weight of up to 17,000 tons. According to GP40-2's figures, a CW44AC could develop 4,305 DBHP. To match the A's performance, it would need between 5,300 and 5,400 DBHP, so it would not match a single A's performance overall. The GE's operating economy would obviously be much better. Again according to GP40-2's figures, a CW60AC would have about 5,895 DBHP. This is beyond the range of an A in daily service. I've found no data for an FEF-3 above 75 mph, so I don't know what it would do with any certainty. Existing information indicates that they were very capable performers in regular service and could reach their design speed (100-110mph) easily. However, they were not record-breakers in the DBHP department according to the small amount of test info available. Don't know why. GP40-2's figures for the P42 indicate that it would develop 3,850 DBHP at 100 mph. This would be pretty rarified atmosphere for steam and is likely well beyond the range of an FEF-3. My guess is that an FEF-3 would develop about 2,500 to maybe 2,700 DBHP at 100. Since I don't have access to much diesel information, I find the relatively high percentage of rated HP making it to drawbar HP unusual. I didn't think they were that efficient from prime mover to rear coupler.
QUOTE: Originally posted by electro-ortcele QUOTE: Originally posted by electro-ortcele In what way was N&W's steam superior? I've heard that UP used low quality coal, but other than that, Big Boy was built by alco, why would alco make intentionally inferior-quality locomotives for UP when they could make good ones for others? Can someone answer this question for me? I'm not trying to make a discussion out of it, I just haven't heard this before, so I'd like to know what it's about
QUOTE: Originally posted by electro-ortcele In what way was N&W's steam superior? I've heard that UP used low quality coal, but other than that, Big Boy was built by alco, why would alco make intentionally inferior-quality locomotives for UP when they could make good ones for others?
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...
QUOTE: Originally posted by electro-ortcele Big Boy was built by Alco, why would Alco make intentionally inferior-quality locomotives for UP when they could make good ones for others?
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
QUOTE: Originally posted by GP40-2 QUOTE: Originally posted by Old Timer Anybody know how to get this back on topic? All I see is a couple of guys trying to out-brain each other. I don't see either one making any particular points on it. Old Timer Exactly, that's why I done dealing with the Trainjunky on this subject. Besides, Oldtimer, everybody who knows anything about steam knows that the N&W's steam was far superior to anything the Union Pacific ran anyway. Anybody want to start a Y6b thread???[:D]
QUOTE: Originally posted by Old Timer Anybody know how to get this back on topic? All I see is a couple of guys trying to out-brain each other. I don't see either one making any particular points on it. Old Timer
QUOTE: Originally posted by GP40-2 A steam locomotive's power curve is exponential in nature... I mean that a steam locomotive's power curve follows the classic Gaussian Distribution Curve (i.e "the Bell Shaped Curve").... ...torque curves are gaussian in nature. Therefore, it is impossible for a steam locomotives power curve NOT to be gaussian in nature.... If you deny that torque curves are gaussian in nature, then your don't fundamentally understand torque.
QUOTE: Originally posted by GP40-2 Man, you just don't give up even when you are wrong! I bet you drive your parents crazy. If you deny that torque curves are gaussian in nature, then your don't fundamentally understand torque. Since you don't have a true fundamental understanding of this stuff, many of your assumptions are wrong from that point forward. The difference between an man and a kid is that a kid whines and cries even when he is wrong. A man, on the other hand, admits his mistakes, learns from the experience, and moves on. Trainjunky, stop being a whiny kid, and learn to be a man.
QUOTE: Originally posted by trainjunky29 QUOTE: Originally posted by GP40-2 QUOTE: Originally posted by trainjunky29 Dear GP40-2, maybe you have established it, but wait one minute: If torque vs. rpm is Gaussian, wouldn't that mean that at 0 rpm's, you would have no torque? And if you have no torque when stopped, then how does a steam locomotive get things moving? Quite the contrary, a steamer's torque is at a maximum at speeds near 0, and only goes down from there. I admit that I may not have the benefit of college mechanical engineering classes, but I can still read a graph. Secondly, wikipedia is an open source document. That makes it MORE reliable--any malicious or ignorant falacies on the sight would soon be corrected by others either well-meaning or more knowledgeable. If you don't want to use wikipedia, then be my guest to pick some other reference. Without a reference, we could very easily end up arguing over two completely different subjects. Finally, why are we dealing with the largest of the large in terms of random numbers? You can model the Big Boy in Monte Carlo routines if you so desire. I personally prefer brass [:)]! And has anybody noticed that we are arguing about stuff completely different than what this topic started about [8D]? Sincerely, Daniel Parks Torque always has to start at zero. You just can't instantly have say 10,000 lbs ft torque out of no where-it has to start somewhere-and that starting point is zero. Now, we are getting into the idea of limits. If you graph the starting torque of any locomotive in small enough increments you will see a ramp up from a zero starting point, a maximum, and a fall back to zero. Second, as you are aware, power is torque X speed. It is possible to have a large torque reading while having zero power. Example: You are pressing hard on a wrench to remove a stuck bolt. When you first place the wrench on the bolt, you don't instantly have maximum force. Your force starts at zero, then your muscles apply all the force they have. If you are applying all your strength, and the bolt still is not turning, you have created maximum torque BUT zero power. Now, the bolt slowly starts to free itself and turn. The torque reading on the wrench will go down, but the power you have produced will go up. Anyway, we were talking about a locomotives power at certain speeds, not it's tractive effort.. I said to graph the Big Boy's Power vs. Speed. I never said for you to graph a locomotives tractive effort curve (which is nothing more than a linear reading of the torque produced by the locomotive's wheels). P.S. Here's a tip for the future: You can say what you want about the Wikipedia, but I guarantee you if you use that thing for a college level paper you will get a nice big fat F on it. I agree with most of this post. I do not, however, agree with your earlier post. Here's why: You said that torque vs. rpm was Gaussian. Certainly torque cannot go from 0 to whatever instantaneously. However, using your bolt example, you could put on, say, 150 foot-pounds, and the bolt would still be stuck. You would have 0 rpm's, but plenty of torque (not Gaussian). Similarly, with a Big Boy, you could have full steam pressure in the cylinders, with full torque, but not be moving (say the train you're coupled to has the hand-brakes applied, and you are on a "cog Big Boy" so the wheel's won't slip) (not Gaussian). Additionally, you said, "Trainjunky, we already established that the locomotive's job is to apply torque to the rails, and torque curves are gaussian in nature. Therefore, it is impossible for a steam locomotives power curve NOT to be gaussian in nature." There are three things here I hold issue with: 1.) A locomotive's job is to apply a force through the coupler to the train. Torque really isn't the issue here, it's the mechanical advantage between the crankpin and the tire on the locomotive's driving wheels (wheel and axle, so to speak) (Galileo once described the wheel as the "perpetual lever"). Then of course you have to figure in the friction between the wheel and the rail. Basically, torque isn't as important as force--the piston puts a linear force on the main rod, which creates torque, which is made into a "rectified" linear force by the wheels. 2.) We've already gotten into torque vs. rpm (or speed) curves, but just to summarize my argument: At zero rpm's (or zero mph), torque can vary from zero to whatever maximum the locomotive can produce. A gaussian torque vs. rpm curve would mean no or practically now torque at 0 rpm's. 3.) You assert that since torque curves are Gaussian in nature, horsepower curves are by default. I deny that torque curves are Gaussian in nature, but let's do a little math: For the sake of arugment, let's ignore the force fluctuations throughout a locomotive wheel's revolution (so that a constant force acts on the wheel all the time). Torque equals the perpendicular force times the radius from which it acts. Therefore, the perpendicular force = torque/radius. The force exerted to the rail is the aforementioned "torquing force" times the crankpin radius devided by the wheel's radius, or F = f x r / R (r/R is a mechanical advantage less than one). Finally, Power = Force x velocity. Now let's do some substitution, and you'll end up with Power = torque x velocity / wheel radius (or because there are 550 foot-pounds in a horsepower, Horsepower = torque x velocity / 550 x wheel radius). But let's just stick with Power = torque x velocity / a constant. We are graphing power vs. speed. Obviously, velocity vs. speed will be a linear graph. Even if torque vs. rpm were Gaussian (which I deny), a Gaussian graph times a linear graph would not be Guassian any more than a sinusoidal graph times a parabolic graph would be sinusoidal. Sincerely, Daniel Parks
QUOTE: Originally posted by GP40-2 QUOTE: Originally posted by trainjunky29 Dear GP40-2, maybe you have established it, but wait one minute: If torque vs. rpm is Gaussian, wouldn't that mean that at 0 rpm's, you would have no torque? And if you have no torque when stopped, then how does a steam locomotive get things moving? Quite the contrary, a steamer's torque is at a maximum at speeds near 0, and only goes down from there. I admit that I may not have the benefit of college mechanical engineering classes, but I can still read a graph. Secondly, wikipedia is an open source document. That makes it MORE reliable--any malicious or ignorant falacies on the sight would soon be corrected by others either well-meaning or more knowledgeable. If you don't want to use wikipedia, then be my guest to pick some other reference. Without a reference, we could very easily end up arguing over two completely different subjects. Finally, why are we dealing with the largest of the large in terms of random numbers? You can model the Big Boy in Monte Carlo routines if you so desire. I personally prefer brass [:)]! And has anybody noticed that we are arguing about stuff completely different than what this topic started about [8D]? Sincerely, Daniel Parks Torque always has to start at zero. You just can't instantly have say 10,000 lbs ft torque out of no where-it has to start somewhere-and that starting point is zero. Now, we are getting into the idea of limits. If you graph the starting torque of any locomotive in small enough increments you will see a ramp up from a zero starting point, a maximum, and a fall back to zero. Second, as you are aware, power is torque X speed. It is possible to have a large torque reading while having zero power. Example: You are pressing hard on a wrench to remove a stuck bolt. When you first place the wrench on the bolt, you don't instantly have maximum force. Your force starts at zero, then your muscles apply all the force they have. If you are applying all your strength, and the bolt still is not turning, you have created maximum torque BUT zero power. Now, the bolt slowly starts to free itself and turn. The torque reading on the wrench will go down, but the power you have produced will go up. Anyway, we were talking about a locomotives power at certain speeds, not it's tractive effort.. I said to graph the Big Boy's Power vs. Speed. I never said for you to graph a locomotives tractive effort curve (which is nothing more than a linear reading of the torque produced by the locomotive's wheels). P.S. Here's a tip for the future: You can say what you want about the Wikipedia, but I guarantee you if you use that thing for a college level paper you will get a nice big fat F on it.
QUOTE: Originally posted by trainjunky29 Dear GP40-2, maybe you have established it, but wait one minute: If torque vs. rpm is Gaussian, wouldn't that mean that at 0 rpm's, you would have no torque? And if you have no torque when stopped, then how does a steam locomotive get things moving? Quite the contrary, a steamer's torque is at a maximum at speeds near 0, and only goes down from there. I admit that I may not have the benefit of college mechanical engineering classes, but I can still read a graph. Secondly, wikipedia is an open source document. That makes it MORE reliable--any malicious or ignorant falacies on the sight would soon be corrected by others either well-meaning or more knowledgeable. If you don't want to use wikipedia, then be my guest to pick some other reference. Without a reference, we could very easily end up arguing over two completely different subjects. Finally, why are we dealing with the largest of the large in terms of random numbers? You can model the Big Boy in Monte Carlo routines if you so desire. I personally prefer brass [:)]! And has anybody noticed that we are arguing about stuff completely different than what this topic started about [8D]? Sincerely, Daniel Parks
QUOTE: Originally posted by trainjunky29 QUOTE: Originally posted by GP40-2 QUOTE: Originally posted by trainjunky29 How is a steamer's power curve related to a Gaussian Curve? 1.) A Gaussian curve returns to 0 as the x-component increases, a steamer's does not 2.) A steam locomotive has nothing to do with probability nor with quantum physics 3.) A steam locomotive's power curve has no points of inflection 4.) I plotted feltonhill's data, and it looks nothing like the curves shown in the above link or a "classic Gaussian distribution curve." Sincerely, Daniel Parks Let's look at the data, and focus on speed vs. hp: Speed - Calc TE (lbs) - Actual DB Pull (lbs) - Actual DBHP 0 - 135,300 - 131,000 - 0 10 - 132,500 - 124,000 - 3,307 20 - 109,000 - 98,000 - 5,227 30 - 83,000 - 75,000 - 6,000 40 - 67,000 - 57,000 - 6,080 50 - 56,100 - 43,000 - 5,733 60 - 48,700 - 32,000 - 5,120 SPEED=X HP=Y X Y 0 0 10 3307 20 5527 30 6000 40 6080 50 5733 60 5120 70 4000 (extrapolated) 80 2800 (extrapolated) Plot those, and you will get a bell shaped curve. Maybe not a "pure Guassian", but a bell shaped curve none the less. I'm also curious why you think probability and statistics can not be used to describe how a steam locomotive works? After all, Monte Carlo routines are often used now in mechanical engineering design... Dear GP40-2, Due to the reasons I have sighted as points 1, 3, and 4 above, a horsepower curve looks little like a Bell-shaped curve. I presume by Monte Carlo Routine you mean what is described here: http://en.wikipedia.org/wiki/Monte_Carlo_method. You will notice that these have to do with random numbers. At the macroscopic locomotive level, as I'm sure you realize, random motions tend to cancel one another out. There's not much that's random on a Big Boy (other than which bolt will rust in place next [:)]). Sincerely, Daniel Parks
QUOTE: Originally posted by GP40-2 QUOTE: Originally posted by trainjunky29 How is a steamer's power curve related to a Gaussian Curve? 1.) A Gaussian curve returns to 0 as the x-component increases, a steamer's does not 2.) A steam locomotive has nothing to do with probability nor with quantum physics 3.) A steam locomotive's power curve has no points of inflection 4.) I plotted feltonhill's data, and it looks nothing like the curves shown in the above link or a "classic Gaussian distribution curve." Sincerely, Daniel Parks Let's look at the data, and focus on speed vs. hp: Speed - Calc TE (lbs) - Actual DB Pull (lbs) - Actual DBHP 0 - 135,300 - 131,000 - 0 10 - 132,500 - 124,000 - 3,307 20 - 109,000 - 98,000 - 5,227 30 - 83,000 - 75,000 - 6,000 40 - 67,000 - 57,000 - 6,080 50 - 56,100 - 43,000 - 5,733 60 - 48,700 - 32,000 - 5,120 SPEED=X HP=Y X Y 0 0 10 3307 20 5527 30 6000 40 6080 50 5733 60 5120 70 4000 (extrapolated) 80 2800 (extrapolated) Plot those, and you will get a bell shaped curve. Maybe not a "pure Guassian", but a bell shaped curve none the less. I'm also curious why you think probability and statistics can not be used to describe how a steam locomotive works? After all, Monte Carlo routines are often used now in mechanical engineering design...
QUOTE: Originally posted by trainjunky29 How is a steamer's power curve related to a Gaussian Curve? 1.) A Gaussian curve returns to 0 as the x-component increases, a steamer's does not 2.) A steam locomotive has nothing to do with probability nor with quantum physics 3.) A steam locomotive's power curve has no points of inflection 4.) I plotted feltonhill's data, and it looks nothing like the curves shown in the above link or a "classic Gaussian distribution curve." Sincerely, Daniel Parks
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