MichaelSol wrote: Even modern music videos look back to the Steam era with some nostalgia, and here is a good example from the Hooters combining a folk classic, slide guitar, some nice Steam footage, and somehow tries to make an interesting connection with Human Rights in China. But notice how strongly the video attaches the idea of Steam to the Great Depression; and identifies Steam in that context.http://www.youtube.com/watch?v=jZwVcsANtWQ
Even modern music videos look back to the Steam era with some nostalgia, and here is a good example from the Hooters combining a folk classic, slide guitar, some nice Steam footage, and somehow tries to make an interesting connection with Human Rights in China. But notice how strongly the video attaches the idea of Steam to the Great Depression; and identifies Steam in that context.
http://www.youtube.com/watch?v=jZwVcsANtWQ
Wow! That 500 miles song by the Hooters together with the video is dynamite. It reminds me of how old and deep the railroad culture runs. Very emotional.
selector wrote: Nicely put, Michael. That expresses neatly what steam has meant for me...a window to our heritage, and an acknowledgement that excellent brains whipped this older technology into dividends and into the viable countries we know today. Fortunately, people even more dedicated and keen than I will take the time to restore some of these fire-breathers and help the rest of us to enjoy them. And, if they do make a "comeback", as the OP asks, I would have to conclude that it would be from the standpoint of someone imagining the coming back of a Ford Fairlane witnessing the reality evinced by the first Toyota Prius on his main street. It just won't be the same.-Crandell
Nicely put, Michael. That expresses neatly what steam has meant for me...a window to our heritage, and an acknowledgement that excellent brains whipped this older technology into dividends and into the viable countries we know today. Fortunately, people even more dedicated and keen than I will take the time to restore some of these fire-breathers and help the rest of us to enjoy them.
And, if they do make a "comeback", as the OP asks, I would have to conclude that it would be from the standpoint of someone imagining the coming back of a Ford Fairlane witnessing the reality evinced by the first Toyota Prius on his main street. It just won't be the same.
-Crandell
selector wrote: And, if they do make a "comeback", as the OP asks, I would have to conclude that it would be from the standpoint of someone imagining the coming back of a Ford Fairlane witnessing the reality evinced by the first Toyota Prius on his main street. It just won't be the same.-Crandell
OK, maybe not a Ford Fairlane, but a hot '68 Mustang...
Bullitt-proof idea?
Ford resurrects Steve McQueen's '68 Mustang for 2008
June 1, 2008 DAN JEDLICKA Auto Editor/djedlicka@suntimes.com
The wild San Francisco car chase between a Ford Mustang GT coupe driven by Steve "Mr. Cool" McQueen and a Dodge Charger in the 1968 movie "Bullitt" defined the modern movie car chase.
Now, Ford is offering a 2008 "Mustang Bullitt" coupe with dark-green paint that closely matches that of the 1968 movie car's and a 315-horsepower V-8. Only 7,700 units of the $30,330 car will be built, each with a unique serial number.
The "Bullitt" movie crew stripped the Mustang of exterior badges and logos to give it an aggressive look.
Ford did the same with the 2008 Bullitt. The 151-mph car even sounds like the movie car.
The interior features black leather and aluminum accents. Developed by Ford's racing unit, the Bullitt has sport suspension, huge tires on special wheels and a five-speed manual transmission -- plus chromed dual exhaust tips.
Ford's hope: that McQueen and his movie car haven't gone out of style.
Steve McQueen drives a Mustange in a car chase in "Bullitt".
MichaelSol wrote: fredswain wrote: The entire point of the example and it's assumptions was to see if there was a trend that corroborated the chart shown here. As an unbiased person in the debate who is trying to learn, I just wanted to see if it holds true. In fact it does which is fascinating. ...What I learned in that exercise was that tractive effort has 3 things that determine it at any speed and with any engine. Those 3 things are torque at the rails, wheel diameter, and weight on the drive wheels. Compare to comments on this thread: Anthony V. wrote:I think the thing that is made up is the concept of equal weight on drivers. It is irrelevant.Anthony V.There are people on these forums, and they almost always nearly show up on the same subjects in the same contexts, who bring not only an extraordinary bias, but a near malice to the conversation. I doubt that I have seen so much personal venom generated as discussions about steam vs diesel, unless it was the contingent that argued about wheat rates ad nauseum -- and not a single one ever apologized after the GAO came out with its landmark study showing that wheat rates had, in fact, increased. Yup, they were flat out wrong. Oddly, it was nearly the same group on these forums that misrepresented that data right and left, that moved on to steam vs diesel.Like you, I had zero interest in, at best, little understanding of, Steam power -- my background was railway electrification, and although I had worked with H.F. Brown, it was on diesel and electric issues, notwthstanding his landmark study on Steam vs. Diesel. I remembered being vaguely surprised at Steam maintenance costs -- it went against my own conventional understanding -- but it was also about a bygone era; certainly one that I was never enamored with, nor had any reason to be interested in. However, a closer look at Brown's paper recently brought forward many questions, and suddenly these forums took on the attitude of "ignore the man behind that curtain" on issues of both performance and economics. I find it very interesting because I've always been under the assumption that a diesel with it's average power being everywhere, should have been the winner. When you only focus on a part of the information though, anything can be made to look like you want it to. This was very fascinating to me.It was a revelation to me as well. I had no idea how well suited Steam power was to the practical needs of railway operation. As someone with a "constant horsepower" background -- traction motors pulling from a catenary -- the idea of a whole different philosophy of propulsion was a little hard to get a handle on. It wasn't intuitive for me at all. Like you, I had to run this through some modelling to convince myself.For me, it goes back to Brown's paper. I consider it a model of its kind. Having worked with Brown, and debated this issue in detail on these forums, I can conclude that there is not one single person here qualified to sharpen Brown's pencils, let alone challenge him on the merits his study.I appreciate your efforts in this regard. Far too few people here are willing to do their homework before they offer opinions. It is the sad sickness of Trains forums.
fredswain wrote: The entire point of the example and it's assumptions was to see if there was a trend that corroborated the chart shown here. As an unbiased person in the debate who is trying to learn, I just wanted to see if it holds true. In fact it does which is fascinating. ...What I learned in that exercise was that tractive effort has 3 things that determine it at any speed and with any engine. Those 3 things are torque at the rails, wheel diameter, and weight on the drive wheels.
The entire point of the example and it's assumptions was to see if there was a trend that corroborated the chart shown here. As an unbiased person in the debate who is trying to learn, I just wanted to see if it holds true. In fact it does which is fascinating.
...What I learned in that exercise was that tractive effort has 3 things that determine it at any speed and with any engine. Those 3 things are torque at the rails, wheel diameter, and weight on the drive wheels.
Compare to comments on this thread:
Anthony V. wrote:I think the thing that is made up is the concept of equal weight on drivers. It is irrelevant.Anthony V.
Anthony V.
There are people on these forums, and they almost always nearly show up on the same subjects in the same contexts, who bring not only an extraordinary bias, but a near malice to the conversation. I doubt that I have seen so much personal venom generated as discussions about steam vs diesel, unless it was the contingent that argued about wheat rates ad nauseum -- and not a single one ever apologized after the GAO came out with its landmark study showing that wheat rates had, in fact, increased. Yup, they were flat out wrong. Oddly, it was nearly the same group on these forums that misrepresented that data right and left, that moved on to steam vs diesel.
Like you, I had zero interest in, at best, little understanding of, Steam power -- my background was railway electrification, and although I had worked with H.F. Brown, it was on diesel and electric issues, notwthstanding his landmark study on Steam vs. Diesel. I remembered being vaguely surprised at Steam maintenance costs -- it went against my own conventional understanding -- but it was also about a bygone era; certainly one that I was never enamored with, nor had any reason to be interested in. However, a closer look at Brown's paper recently brought forward many questions, and suddenly these forums took on the attitude of "ignore the man behind that curtain" on issues of both performance and economics.
I find it very interesting because I've always been under the assumption that a diesel with it's average power being everywhere, should have been the winner. When you only focus on a part of the information though, anything can be made to look like you want it to. This was very fascinating to me.
It was a revelation to me as well. I had no idea how well suited Steam power was to the practical needs of railway operation. As someone with a "constant horsepower" background -- traction motors pulling from a catenary -- the idea of a whole different philosophy of propulsion was a little hard to get a handle on. It wasn't intuitive for me at all. Like you, I had to run this through some modelling to convince myself.
For me, it goes back to Brown's paper. I consider it a model of its kind. Having worked with Brown, and debated this issue in detail on these forums, I can conclude that there is not one single person here qualified to sharpen Brown's pencils, let alone challenge him on the merits his study.
I appreciate your efforts in this regard. Far too few people here are willing to do their homework before they offer opinions. It is the sad sickness of Trains forums.
The concept of equal weight on drivers IS irrelevant.
For example, the Big Boy weighed in at over 1,100,000 lb, locomotive and tender. The FT locomotive set weighed in at about 1,000,000 lb ( I've seen figures as low as 900,000 lb up to 1,200,000 lb).
Because the Big Boy required leading and trailing trucks and an enormous tender, it could put only about 540,000 lb of this weight toward producing traction.
The FT could put ALL of its weight (whatever the exact figure is) toward producing traction.
Why should the Diesel be penalized because it doesn't need the leading and trailing trucks and a massive tender to do its job?
Further, what if a "modern" steam engine was built that weighed in at 1,100,000 lb and somehow did put all its weight on the drivers? Would this be superior to the Big Boy? Or, would we compare the two by forcing the modern steam engine to only have 540,000 lb on drivers? Of course we wouldn't.
The fact that most Diesels do put all their weight on drivers represents a fundamental advantage over practically every steam engine ever built. Forcing them to have equal weight on drivers as a steam engine unfairly strips them of that advantage.
AnthonyV wrote: fredswain wrote: The entire point of the example and it's assumptions was to see if there was a trend that corroborated the chart shown here. As an unbiased person in the debate who is trying to learn, I just wanted to see if it holds true. In fact it does which is fascinating. Why should the Diesel be penalized because it doesn't need the leading and trailing trucks and a massive tender to do its job?...The fact that most Diesels do put all their weight on drivers represents a fundamental advantage over practically every steam engine ever built. Forcing them to have equal weight on drivers as a steam engine unfairly strips them of that advantage.
fredswain wrote: The entire point of the example and it's assumptions was to see if there was a trend that corroborated the chart shown here. As an unbiased person in the debate who is trying to learn, I just wanted to see if it holds true. In fact it does which is fascinating.
Why should the Diesel be penalized because it doesn't need the leading and trailing trucks and a massive tender to do its job?...The fact that most Diesels do put all their weight on drivers represents a fundamental advantage over practically every steam engine ever built. Forcing them to have equal weight on drivers as a steam engine unfairly strips them of that advantage.
Well, sorry, I've been around the BN Diesel-electric fuel tenders. Just don't recall the "massive tender" argument or else those poor dumb b******s just don't understand railroading as well as you do ....
If you will re-read Fred's calculations, you will see that the Steam advantage in Tractive Effort occurs before the power even gets to the rail, drivers or otherwise, irrespective of the weight on the drivers.
Are you trying to "unfairly" strip Steam of that advantage? Why do you take such an obviously personal interest that compels you to intentionally misrepresent that, ironically, in the posture of a transparently feigned indignation regarding "unfairness"?
Weight is not relevant to tractive effort. It is relevant to adhesion though. Keep in mind that the train wouldn't move if there was no adhesion. If we are looking at pure tractive effort the simulated steam engine vs diesel that I ran calulations on did in fact outdo the diesel quite early in terms of TE. In order to see which would could in fact move a train down the rails better however, TE doesn't tell us enough on it's own. We NEED to know adhesion. A modern diesel has computer control over adhesion that the steam engines never had. However with the TE advantage, does the adhesion abilities of a modern diesel in accordance with traction control have enough to offset or overcome the steam engine's TE advantage at speed? That is the real question that I think everyone wants to know when comparing engines of like horsepower and I'm not sure it is one that we can directly answer. If someone can give me some performance charts for a steam and diesel engine of like power and let me know other info such as traction motor rating, gearing, steam engine boiler pressure, piston stroke and bore, as well as wheel diameter for each, I'll figure this out on a comparative chart.
f
daveklepper wrote:Steam locomotive engineers did not need computer controls to have some adhesion control, since they could play the Johnon Bar (the reverser and cutoff control), against the throttle, to accomplish the same effect, and the control was less critical because of the side-rod connection between drivers: either all drivers slipped or none did. This applies to two cylinder locomotives, and additional controls made possible extending this control to four-cylinder locomotives. Skill replaced computers.
Dave,
It would be more accurate to say that "computers replaced skill". The Pennsy T-1 had an unjustified reputation as being slippery. A light throttle and some sand until you reached about 15mph when you could start to open her up and a T-1 would walk away with a 20 car train with nary a slip. Some enginemen never quite got the hang of this and operated them like they would the K-4 Pacifics they were used to running. The T-1's had a greater power to weight on drivers ratio than did the K-4's and had to be operated differently or yes they would slip.
Mark
It seems to me we've danced around the TE/Wt. on driving wheels issue a good bit and I'll try to express it in a practical way. We all know that virtually all locomotives, whether they be steam or diesel electric, are capable of producing more than enough power to cause wheel slippage. This is true from 0mph up to some maximum speed which varies with the specifics of each engine and operating conditions, e.g. wet vs dry rails.
Since the purpose of a locomotive is to pull a train, what counts is the tractive effort that is produced at the drawbar which I like to think of as "effective" tractive effort. This is the pulling power that enables an engine to start a train and accelerate it and maintain speed. Up to the maximum speed referred to in the preceding paragraph this effective TE is limited to what can be produced at the drawbar without loss of adhesion. Since the upper limit of adhesion is basically governed by the weight on the powered wheels x the coeffecient of adhesion, the effective TE is very much a function of the weight on the driving wheels. Since trains are dispatched in all kinds of weather the effective TE is further limited by the lower coeffecients of adhesion that prevail under various adverse conditions.
As higher speeds are reached the power any engine can produce decreases until it no longer is capable of exerting a driving force that exceeds its upper limit of adhesion. At speeds above this point adhesion is no longer a limitation and the effective TE becomes a function only of the engines power producing ability.
I don't think it's been discussed previously but in practice the tonnage rating of a locomotive is more useful than is its TE or horsepower. Tonnage rating is the gross weight of a train that can be handled by a given locomotive on a specific stretch of trackage (usually a division or subdivision) at the speeds necessary to maintain desired schedules. In addition to the engines effective tractive effort it takes into consideration mainly track curvature and ruling grades. Tonnage ratings are used to determine how many locomotives to assign to a train of a given weight.
In the fifth and sixth preceding posts above:
AnthonyV said:
"The concept of equal weight on drivers IS irrelevant."
MichaelSol said:
"If you will re-read Fred's calculations, you will see that the Steam advantage in Tractive Effort occurs before the power even gets to the rail, drivers or otherwise, irrespective of the weight on the drivers."
It appears that you two are making the same point in agreement, yet the contexts of your posts make it sound like you are disagreeing over the point. Why is that?
Bucyrus wrote: In the fifth and sixth preceding posts above:AnthonyV said:"The concept of equal weight on drivers IS irrelevant."MichaelSol said:"If you will re-read Fred's calculations, you will see that the Steam advantage in Tractive Effort occurs before the power even gets to the rail, drivers or otherwise, irrespective of the weight on the drivers."It appears that you two are making the same point in agreement, yet the contexts of your posts make it sound like you are disagreeing over the point. Why is that?
He believes that the dynamometer car measurements which correlate actual TE to weight on drivers is "unfair" to the Diesel-electric. My point is that since the TE of the Steam engine exceeds that of the Diesel-electric at higher speeds independent of the weight on the drivers, but for reasons which reside in the differing physics of the two types of motive power, how does that "penalize" the Diesel-electric? There seems to be a "desire" -- and that's the only way I can characterize arguments that are made in terms of "unfairness" and "penalties" -- to select particular metrics that don't really offer meaningful correlations, while avoiding tangible mathematical and dynamometer evidence that exists to the contrary.
Mark, your description just above is very good, and it works for me. I had understood it by then, but I think your post should help others who may be struggling a bit falling one way or the other to make up their minds. Thanks for taking the time to compose and post it.
selector wrote: Mark, your description just above is very good, and it works for me. I had understood it by then, but I think your post should help others who may be struggling a bit falling one way or the other to make up their minds. Thanks for taking the time to compose and post it.-Crandell
Mark's explanation is perfectly clear to me. So is Fredswain's explanation in post #2 of the Steam vs diesel: power at speed thread.
Bucyrus:
You answered your own question.
In the "Diesel vs. Steam: power at speed" thread you stated the following:
"With all due respect, I must ask again: What is comparable about the two locomotives? You are comparing a steamer to a diesel with the steamer having higher maximum horsepower and higher tractive effort than the diesel. And then you conclude that the steam locomotives in general are fundamentally better than diesels in general at producing tractive effort. "
The equal weight on drivers is an arbitrary point of comparison that reinforces the circular logic you discussed above.
AnthonyV wrote: Bucyrus:You answered your own question.In the "Diesel vs. Steam: power at speed" thread you stated the following:"With all due respect, I must ask again: What is comparable about the two locomotives? You are comparing a steamer to a diesel with the steamer having higher maximum horsepower and higher tractive effort than the diesel. And then you conclude that the steam locomotives in general are fundamentally better than diesels in general at producing tractive effort. "The equal weight on drivers is an arbitrary point of comparison that reinforces the circular logic you discussed above. Anthony V.
Nothing circular about it. If you want "comparable" engines, then look for comparable engines. If you have two engines asked to just about the same work from 0 mph, and they are doing it, the problem is that the Diesel-electric reaches its peak at about 19 mph. Well, if its asked to do the same work, the Steam engine can reach that same h.p. at 19 mph. Nothing wrong with that, is there?
Now, two engines doing the same work at that point must be "equivalent" in some fashion, since they are doing the same work. And they are able to do so in part because of the same weight on the drivers. And has been pointed out, h.p. is the work. So, by the definition, these engines are equivalent.
But, the Diesel-electric can't generate any more hp after 19 mph. Well, that's the problem, isn't it? The Steam engine can continue to develop more h.p. after 19 mph. That's not a problem with the Steam engine.
The Steam engine that can do the equivalent work as the Diesel-electric does so right up to 19 mph, when the Diesel-electric loses its capacity to continue to develop additional horsepower. But it makes zero sense to impose that limit on the Steam engine, which is exactly what you are doing by making that limit the MAXIMUM that the Steam engine is ALLOWED to develop over the remainder of the power curve.
The equivalent Steam locomotive simply continues to develop horsepower and that is characteristic of the Steam locomotive even as it is different than the equivalent Diesel-electric. It is the Diesel-electric that loses its capability to remain "equivalent", not the Steam engine, after 19 mph.
So, exactly what is accomplished by saying that, at 19 mph, we are going to change the rules? We don't want a locomotive that can achieve the same amount of work as a Diesel-electric between 0 and 19 mph, we want a substantially smaller steam engine working throughout that curve so that -- when the steam engine finally does reach its maximum output, it is the maximum number at 60 mph, or so, that is equal to the number reached when our Diesel-electric pooped out at 19 mph. But, the load characteristic of the train is fundamentally different at 60 than at 20, so there is nothing comparable about that either...
Yes, then you have a substantially smaller steam engine that cannot do the work of the Diesel-electric through its cycle, because you imposed the Diesel-electric's limit at the peak of its cycle -- at 19 mph -- on the Steam engine at the peak of its cycle -- 40 mph later.
Why?
There is absolutely no actual reason except to compare a significantly smaller Steam engine with a larger Diesel-electric. If that's the answer you want, you get it, but it has nothing to do with comparing similar locomotives because you remove all meaningful similarities -- the ability to do similar work at similar speeds -- by simply saying that the steam locomotive that can do so is not comparable, and you refuse to acknowledge that two machines operating through -- practically speaking -- 90% of their load cycle are not comparable if they are, in fact, comparable and able to do the same work; but the the idea of "comparable" is adjusted to meet a highly artificial definition that is only designed to limit the performance of the Steam engine to what the Diesel-electric can do at 19 mph. Well, by substituting a small steam engine that isn't comparable in any way, shape or form, yes, that can be done.
But, that's circular.
The fact is that the comparable Steam engine is working pretty well next the Diesel-electric below 20 mph, and simply continues to develop the hp after that point that the Diesel-electric is unable to develop. In an honest comparison, that is a feature, not a handicap.
If you want to examine the joke practically, ask the guy that purchases motive power. If he wants to buy "equivalent" locomotives to do the same work on the same trains, and spend the money to do so, is he really interested in a hypothetical regarding two locomotives that are not comparable at all?
He is going to tell you, if they both can't move the train from 0 to 20 in something resembling the same amount of time, then they're not comparable. He wouldn't be interested because the artificial imposition of a limit of one locomotive on a different part of the power curve of a different locomotive, while perhaps of theoretical interest to somebody for some ulterior motive, has nothing to do with the fact that comparable locomotives move comparable trains; and the Diesel-electric simply loses its ability to do so at an earlier point on its power curve.
He will absolutely not be convinced that they are "comparable" motive power under the hypothetical proposed here because that is a joke that has nothing to do with what a motive power superintendent is interested in when he speaks in terms of "comparable" power.
I think if this was proposed to anyone in the real world, the first question would be: "why" since it has nothing to do with actually pulling comparable trains, which is absolutely and ultimately what "comparable" motive power is all about.
And as soon as somebody started to argue that the "maximum hp at 60" for one is the same for the other at 20, and that by this odd standard they are comparable ... I have absolutely no doubt that the gentlemen on this thread that think that makes any sense at all to anyone on a railroad who is actually thinking about moving trains would be escorted to the door ... perhaps more quickly than politely.
I must be missing something in this argument.
Diesels hit their maximum torque at reletively low RPM. That is not because of the diesel, it is because electric motors make great low end torque.
It does not fall off from there. It just doesn't get higher torque as it speeds up.
I don't know much about steam, but if I am reading the pro steam argument correctly, steam engines reach their maximum torque at a much higher speed. Therefore, to me at least, the argument does seem circular. You seem to be using the 19 MPH horsepower to declare that the engines are similar when, in fact, you should be using MAXIMUM horsepower, to determine whether the engines are similar power.
If you are comparing a deisel that makes 5,000 HP at 19 MPH to a steam engine that makes 5,000 HP at 19 MPH, but 10,000 HP at 70 MPH, then you are comparing a 5K engine to a 10K engine. If they both make 5K at 70 MPH, then the steam engine will only make 2500 HP at 19 MPH, so clearly the deisel is superior.
Why do you suppose all the 200 to 300 MPH trains are electric? Electric traction motors are the most efficient way to deploy the power. Ships used to run steam, but they don't anymore except for the nukes. Heavy construction cranes used to be steam powered, but they aren't anymore.
If steam is so superior, as the argument claims, don't you suppose SOMEONE would still be using it?
Dave
Lackawanna Route of the Phoebe Snow
Phoebe Vet wrote: I don't know much about steam, but if I am reading the pro steam argument correctly, steam engines reach their maximum torque at a much higher speed. Therefore, to me at least, the argument does seem circular. You seem to be using the 19 MPH horsepower to declare that the engines are similar when, in fact, you should be using MAXIMUM horsepower, to determine whether the engines are similar power.
And, if your primary purpose is to move trains, and every single train has to move between 0 and 20, and probably 90% of train movement occurs in that range, why would you be interested in "maximum" horsepower at an irrelevant number at all? The fact is, the diesel-electric's maximum hp occurs at 19 mph. That is not irrelevant -- it is entirely significant because a comparable steam engine developing that same maximum at that same speed, continues to develop hp.
On metrics, that Steam engine is comparable on hp, on speed, and on weight on drivers -- that's three axes of comparison that demonstrates true statistical comparability. If you understand statistics at all, you will understand that comparability is not something arbitrary that you make up to support a point of view. It is a statistical measure and the measure I advocate here has much higher statistical correlation than comparing hp at two completely different points on a power curve.
And that's not an accident that it shows up in the real world, nor is it ironic that when a railroad talks in terms of "comparable" motive power -- it is based on those criteria because they relate to how the power will pull the same trains. And the fact that that Steam engine will develop over 7,000 hp whereas the Diesel-electric is only over 5,000 is in fact a measure of MAXIMUM horsepower and if that is the important criteria to you, then you should, in fact, choose the locomotive with the higher MAXIMUM horsepower, while actually offering comparable performance over a normal operating range. That happens to be the Steam engine.
And that is what is circular here: you talk about MAXIMUM horsepower, in great big letters, and then try to figure out a way not to choose it ...
I'm going to bow out of this.
I know "My mind is made up, don't try to confuse me with facts" when I hear it.
For what it's worth, I don't have a horse in this race. I was just trying to digest the arguments I have been reading here. My personal preference is electrification. I have no problem with using coal to generate the electricity if it's practical.
MichaelSol wrote: Phoebe Vet wrote: I don't know much about steam, but if I am reading the pro steam argument correctly, steam engines reach their maximum torque at a much higher speed. Therefore, to me at least, the argument does seem circular. You seem to be using the 19 MPH horsepower to declare that the engines are similar when, in fact, you should be using MAXIMUM horsepower, to determine whether the engines are similar power.And, if your primary purpose is to move trains, and every single train has to move between 0 and 20, and probably 90% of train movement occurs in that range, why would you be interested in "maximum" horsepower at an irrelevant number at all? The fact is, the diesel-electric's maximum hp occurs at 19 mph. That is not irrelevant -- it is entirely significant because a comparable steam engine developing that same maximum at that same speed, continues to develop hp.On metrics, that Steam engine is comparable on hp, on speed, and on weight on drivers -- that's three axes of comparison that demonstrates true statistical comparability and it is not ironic that when a railroad talks in terms of "comparable" motive power -- it is based on those criteria because they relate to how the power will pull the same trains. And the fact that that Steam engine will develop over 7,000 hp whereas the Diesel-electric is only over 5,000 is in fact a measure of MAXIMUM horsepower and if that is the important criteria to you, then you should, in fact, choose the locomotive with higher MAXIMUM horsepower. That happens to the be the Steam engine.
On metrics, that Steam engine is comparable on hp, on speed, and on weight on drivers -- that's three axes of comparison that demonstrates true statistical comparability and it is not ironic that when a railroad talks in terms of "comparable" motive power -- it is based on those criteria because they relate to how the power will pull the same trains. And the fact that that Steam engine will develop over 7,000 hp whereas the Diesel-electric is only over 5,000 is in fact a measure of MAXIMUM horsepower and if that is the important criteria to you, then you should, in fact, choose the locomotive with higher MAXIMUM horsepower. That happens to the be the Steam engine.
Yes but couldn't you just add a couple more diesel units to that FT locomotive and make it more powerful than the steamer? Would that then change the conclusion about the performance of steam versus diesel?
Bucyrus wrote: Yes but couldn't you just add a couple more diesel units to that FT locomotive and make it more powerful than the steamer? Would that then change the conclusion about the performance of steam versus diesel?
Then you are losing all your axes of correlation -- hp, speed and weight on drivers -- and there remains no basis to use the word "comparable" because there is no statistical comparability.
Add another Steam engine. Would that change the conclusion about the performance of steam vs diesel? No, because you would lose all the axes of correlation there too, although if you were really sincere about this quest for MAXIMUM horsepower, that would certainly be a way to do it cheaply compared to the Diesel-electric alternative.
MichaelSol wrote:The fact is, the diesel-electric's maximum hp occurs at 19 mph.
During the 1940s and 50s, this would have been more of an advantage for the steam locomotive, when it was the engine's job to move the train 120 miles from one division point to the next. Now we have unit trains running long distances, and meeting ruling grades. Running these trains with steam power would either require overpowering or the return of helper districts.
nanaimo73 wrote: MichaelSol wrote:The fact is, the diesel-electric's maximum hp occurs at 19 mph.During the 1940s and 50s, this would have been more of an advantage for the steam locomotive, when it was the engine's job to move the train 120 miles from one division point to the next. Now we have unit trains running long distances, and meeting ruling grades. Running these trains with steam power would either require overpowering or the return of helper districts.
And your point would be what?
What is overpowered? What does that mean? In what context?
You don't think those long distance trains aren't, "overpowered," now, especially when it comes to fuel costs for the numerous units required to move these trains at any decent average speed for any given time?
Again, how does changing a non relative parameter change the basic characteristics of the two types of power?
Where is it written in stone that steam locomotive utilization would be the same now as it was three quarters of a century ago?
Phoebe Vet wrote: You seem to be using the 19 MPH horsepower to declare that the engines are similar when, in fact, you should be using MAXIMUM horsepower, to determine whether the engines are similar power.
You seem to be using the 19 MPH horsepower to declare that the engines are similar when, in fact, you should be using MAXIMUM horsepower, to determine whether the engines are similar power.
The Steam engine does the equivalent work as the Diesel-electric right up to 19 mph, when the Diesel-electric loses its capacity to continue to develop additional horsepower.
But, throughout that range, those engines can do comparable work. In the real world, those are comparable engines. Among other similarities, such as work, they have comparable weight on their drivers.
But then it makes zero sense to impose the Diesel-electric's limit at that speed on the Steam engine at all speeds, which is exactly what you are doing by making that specific limit - the ability of BOTH engines to deliver the same performance at 19 mph -- the MAXIMUM that the Steam engine is ALLOWED to develop over the remainder of the power curve.
That is not a physical limitation: the Steam engine can continue to develop power. It's simply an artificial limit that seeks to impose the Diesel-electric's limitation on the Steam engine and argue the completely false implication that the Steam engine couldn't develop additional power -- and that is simply false.
And make that clear: you are saying that a Diesel-electric and a Steam engine that are comparable, aren't really comparable if the diesel-electric reaches a limit that does not limit the Steam engine. Well, that will teach those Steam engines ...
What's the point, except to find a small Steam engine that doesn't deliver anything equivalent to the Diesel-electric. Maybe that is the point ...
The analogy would be that its not really a fair fight between you and another if you are the same age and weight and conditioning. It is a fair fight if you are 19, weigh three times as much, and he is 60.
And you argue that is "comparable."
The only salvation on Trains forums is that there are people here that believe that makes complete sense.
What are the limitations on Diesel electrics that they can't develop HP at higher speeds per hp?
I assume that size of the wheels plays some part. Obviously, the nature of the reciprocating transmission is what makes the Steam Horsepower curve what it is.
Some of this has been gone over before, but what's the rate of fuel consumption for the diesel and the steam engine across those curves. Lets assume for the sake of argument that both engines are using some form of liquified coal product for fuel.
Obviously after that, the question is one of water consumption versus lubricant consumption etc.
My point about asking these questions is of course to find out what the costs are of developing that horsepower.
I feel like this thread has covered two very broad topics. "Is steam better than diesel "on the dynometer" and, is steam better than diesel environmentally.
The first question is pretty obvious. The second is a little more ambiguous, but also more immediately relevent. There's no reason an internal combustion/electric can't run on the same fuel source, so strip that boondoggle from the equations. What is the fuel consumption curve, what is the power curve, what is my desired speed.
From that you can get a pretty good equivelency. Given enough fuel and engines for either, the two engine types can each pull a train of any size at any speed the track can support. The answer could end up being that both perform certain tasks well. perhaps grainger lines with flat terrain and high speeds will move back to steam and mountain districts stick with AC traction D/E. Or it could be that some new design that is neither D/E nor reciprocating steam takes over.
YoHo1975 wrote: What are the limitations on Diesel electrics that they can't develop HP at higher speeds per hp?
The primary limiting factor for how much drawbar horsepower can be be generated by a diesel electric is how much power can be generated by diesel engine itself and the efficiency of the electric transmission. A secondary limiting factor is adhesion, below a speed that depends on the maximum output of the diesel engine, the weight on drivers, the conditions of the rail (e.g. dry or wet), the sophistication of the traction control system, the drawbar horsepower will be limited by adhesion.
The best a diesel electric locomotive can do is produce slightly over 0.9 drawbar horsepower for each horsepower available for traction from the diesel engine. Recent locomotives with AC transmissions are capable of this from under 20 MPH to 60 to 70 MPH.
So then, what are the fuel consumption curves?
Here are the consumption numbers for a 12-710G3A (07/1988)
which I got from poster Robbman on trainboard.com
TP ___ RPM ___ HP ___ GPH 8 ____ 904 __ 3030 __ 147.3 7 ____ 820 __ 2253 __ 116.7 6 ____ 729 __ 1502 __ 79.6 5 ____ 651 __ 1244 __ 67.1 4 ____ 568 __ 1000 __ 50.7 3 ____ 490 __ 675 ___ 34.8 2 ____ 343 __ 350 ___ 18.9 1 ____ 269 __ 191 ___ 13,1 Idle __ 200 __ 0 _____ 2.4 DB-6 _ 729 __ 0 _____ 18.6 DB-4 _ 568 __ 0 _____ 10.9 DB-1 _ 269 __ 0 _____ 4.4
What are the consumption curves for a steam engine,I'm not sure what steam engine might be comparable based on the arguments back and forth.
Yoho,
Read this thread from the beginning and you will find what you are looking for. Michael Sol has posted numbers showing cost per btu. With that comparison you do not have to burn the same fuel to make a valid point. He shows that a coal burning steam locomotive produces btus MUCH more economically than a diesel can burn diesel fuel. And therein lies the origin of this whole thread: Given the price of diesel vs. coal, does it make economic sense to bring steam back? The answer seems to be a resounding YES!
Some have asked if steam is so preferable, then why are we not seeing the transition? They forget that the rise in oil prices has been very rapid. Many economists predict a collapse in oil prices from $120 per barrel to around $80. Given the volatility in the current oil market and the uncertainty about worldwide reasponse to it, it is not surprising that railroads are not ready to ditch the diesel. Give it some time. When prices settle to a more permanent level you will likely see railroads beginning to experiment with alternative fuel sources.
tpatrick wrote: Some have asked if steam is so preferable, then why are we not seeing the transition?
Some have asked if steam is so preferable, then why are we not seeing the transition?
Simply put it takes time to develop a concept and a prototype, and then to build it.
The return of steam doesn't mean that we pull all steamers out of tourist operations and museums, overhaul them and set them back on active rails. Any appropriate return of steam powered locomotives would be more in line with the ideas developed for the ill-fated AC3000. In principle the AC3000 had some great advantages but it was never taken from concept to an actual locomotive. More about the AC3000 can be found at this url: http://www.trainweb.org/tusp/ult.html
Additional information can be found at the following websites:
http://www.trainweb.org/tusp/ace.html
http://www.trainweb.org/tusp/ace_det.html
http://www.freepatentsonline.com/4425763.html
The ideas developed with the ACE 3000 are good ones, many of which are key to creating a modern day steam locomotive. The real question is whether or not railroads will consider this as an option and back such an endeavor... but given that diesel fuel and all remains so high they need to be taking a serious look at it.
Here's a 21st century steam engine design proposal:
http://www.5at.co.uk/
I did find this quote very interesting from the AC3000 page:
The ACE 3000 was to be capable of 3000 (nominal) draw bar horsepower (4000 hp peak), an efficient operating speed range of 15 to 70 MPH, have computer-controlled firing, and a typical (not peak) thermal efficiency of 15%. While the ACE team acknowledged that this efficiency was much less than a modern diesel-electric locomotive (which had an efficiency of about 30%), they knew that the immense cost difference in coal and diesel oil would allow a less-efficient coal burning locomotive to be much more economical to fuel than a very efficient oil burning diesel locomotive.
They were designing an advanced steam locomotive but it's efficiency was only half of the comparable diesel of the time. They were relying on the fact that coal was cheaper. Today with environmental and emissions concerns, especially with coal as a fuel source, as well as today's prices, would coal cost half as much as diesel fuel to use? This may be a viable engine to use for coal trains but I can't see it working everywhere as then you have to create the infrastructure to have on site coal which we no longer do not to mention the fact that you'd have to haul it to locations that never see coal.
I love steam but let's be realistic, it's never coming back.
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