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Could steam make a comeback?

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Posted by MichaelSol on Thursday, May 29, 2008 9:12 PM
 GP40-2 wrote:
 MichaelSol wrote:

 GP40-2 wrote:

Have them right in front of me. However, I have ask you, MichaelSol, and wsherrick multiple times your connections with the coal industry/mining industry and how mining MORE coal was going to benefit the environment.

Still waiting for that answer from all three of you.

My connections with the coal industry are probably less than your apparent connections to oil industry.



I have ZERO connections with the oil industry. So, I can infer from your statement that you do have some vested interest in the coal/coal mining industry for increased coal use. Hmmmm....

You just like this don'cha? Make you all warm and fuzzy that there's an ulterior motive behind everything you disagree with so that you can pose as the virgin bride, all pure and simple.

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Posted by GP40-2 on Thursday, May 29, 2008 9:14 PM
 MichaelSol wrote:
 GP40-2 wrote:
 Norman Saxon wrote:
Still waiting on that AC6000 horsepower curve there jeepee.

The steam advocates provided theirs, now you provide yours.



Have them right in front of me. However, I have ask you, MichaelSol, and wsherrick multiple times your connections with the coal industry/mining industry and how mining MORE coal was going to benefit the environment.

Still waiting for that answer from all three of you.

Moderators, is there a reason that this gentleman is always permitted to engage in gratuitous and ad hominmen remarks that only indulge his penchant for insults at the sacrifice of any useful content?

 



How is asking your connections with the coal industry insulting? Considering you are advocating a return to COAL powered steam locomotives, your connections and bias towards coal is very useful for ALL of us in this discussion.
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Posted by MichaelSol on Thursday, May 29, 2008 9:17 PM

 GP40-2 wrote:

That's interesting MichaelSol. What specific steam locomotive did you use to produce the 8,400 HP? The C&O's H8 Allegheny - the most powerful steam locomotive ever built - "only" produced 6,600 DBHP at 45-50 MPH, with a DECLINING HP curve above 50 MPH.

And which Diesel-electric generated 5,600 hp in that era? Missed that, didn't you? Actually, no, it is consistent that you like to mix up modern machines with 50 year old machines, and claim a revelation. It's part of your game. The chart is on a comparable horsepower basis. You can take it down to 1 hp if you like, or 100,000 if you like. The relationships hold based on generally accepted motive power curves.

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Posted by GP40-2 on Thursday, May 29, 2008 9:18 PM
 MichaelSol wrote:
You just like this don'cha? Make you all warm and fuzzy that there's an ulterior motive behind everything you disagree with so that you can pose as the virgin bride, all pure and simple.



Now, who is insulting who?
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Posted by MichaelSol on Thursday, May 29, 2008 9:20 PM
 GP40-2 wrote:
 MichaelSol wrote:
 GP40-2 wrote:
 Norman Saxon wrote:
Still waiting on that AC6000 horsepower curve there jeepee.

The steam advocates provided theirs, now you provide yours.



Have them right in front of me. However, I have ask you, MichaelSol, and wsherrick multiple times your connections with the coal industry/mining industry and how mining MORE coal was going to benefit the environment.

Still waiting for that answer from all three of you.

Moderators, is there a reason that this gentleman is always permitted to engage in gratuitous and ad hominmen remarks that only indulge his penchant for insults at the sacrifice of any useful content?



How is asking your connections with the coal industry insulting? Considering you are advocating a return to COAL powered steam locomotives, your connections and bias towards coal is very useful for ALL of us in this discussion.

"All of us"? You and which mouse?

My single connection with the coal industry was as a charter member of the Northern Plains Resource Council. Dring that time, and while I was his student, my major professor was completing his work: K. Ross Toole, The Rape of the Great Plains: Northwestern America, Cattle and Coal. Boston: Little, Brown and Co., 1976. I chaired a published debate between Dr. Toole and Dr. Mel Morris, a pre-eminent authority on coal land reclamation.

Why do you advocate chaining the US economy to foreign politics, using a fuel that can't meet emission standards currently met by coal?

 

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Posted by MichaelSol on Thursday, May 29, 2008 9:21 PM

 GP40-2 wrote:
 MichaelSol wrote:
You just like this don'cha? Make you all warm and fuzzy that there's an ulterior motive behind everything you disagree with so that you can pose as the virgin bride, all pure and simple.


Now, who is insulting who?

It's no insult, it's true. You're a poseur and you've been insulting people all through this thread. I'm finally fed up with it.

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Posted by tattooguy67 on Thursday, May 29, 2008 9:22 PM
 GP40-2 wrote:
 Norman Saxon wrote:
Still waiting on that AC6000 horsepower curve there jeepee.

The steam advocates provided theirs, now you provide yours.



Have them right in front of me. However, I have ask you, MichaelSol, and wsherrick multiple times your connections with the coal industry/mining industry and how mining MORE coal was going to benefit the environment.

Still waiting for that answer from all three of you.

You have been asked numerous times in these posts to produce facts and figures to back up what you say and in almost all those occasions you have not, i my self asked you what the enviromental costs of an oil refinery are and am still waiting for an answer to that, i can only speak for myself here but it is very clear you think coal is the devil incarnate and under no circumstances would be in favor of it's use, we get that, you have made your point, but i must remind you that the reason i started this thread was the rising cost of oil and our need to look elsewhere so we can move goods around the country, i can only guess that you live some where that has been adversly affected by coal mining and for that you have my sympathies sir, but in the finale analysis we are going to need some thing other than pie in the sky theories to get the job done, and as i and others here see it coal looks like a good solution.

Chuck

Is it time to run the tiny trains yet george?! is it huh huh is it?!
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Posted by wsherrick on Thursday, May 29, 2008 9:25 PM
 MichaelSol wrote:
 GP40-2 wrote:
 Norman Saxon wrote:
Still waiting on that AC6000 horsepower curve there jeepee.

The steam advocates provided theirs, now you provide yours.



Have them right in front of me. However, I have ask you, MichaelSol, and wsherrick multiple times your connections with the coal industry/mining industry and how mining MORE coal was going to benefit the environment.

Still waiting for that answer from all three of you.

Moderators, is there a reason that this gentleman is always permitted to engage in gratuitous and ad hominmen remarks that only indulge his penchant for insults at the sacrifice of any useful content?

 

M. Sol: I second your comment.

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Posted by tattooguy67 on Thursday, May 29, 2008 9:27 PM
 wsherrick wrote:
 MichaelSol wrote:
 GP40-2 wrote:
 Norman Saxon wrote:
Still waiting on that AC6000 horsepower curve there jeepee.

The steam advocates provided theirs, now you provide yours.



Have them right in front of me. However, I have ask you, MichaelSol, and wsherrick multiple times your connections with the coal industry/mining industry and how mining MORE coal was going to benefit the environment.

Still waiting for that answer from all three of you.

Moderators, is there a reason that this gentleman is always permitted to engage in gratuitous and ad hominmen remarks that only indulge his penchant for insults at the sacrifice of any useful content?

 

M. Sol: I second your comment.

And as the starter of this one i will third that big time!
Is it time to run the tiny trains yet george?! is it huh huh is it?!
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Posted by GP40-2 on Thursday, May 29, 2008 9:28 PM
 MichaelSol wrote:

 GP40-2 wrote:

That's interesting MichaelSol. What specific steam locomotive did you use to produce the 8,400 HP? The C&O's H8 Allegheny - the most powerful steam locomotive ever built - "only" produced 6,600 DBHP at 45-50 MPH, with a DECLINING HP curve above 50 MPH.

And which Diesel-electric generated 5,600 hp in that era? Missed that, didn't you? Actually, no, it is consistent that you like to mix up modern machines with 50 year old machines, and claim a revelation. It's part of your game. The chart is on a comparable horsepower basis. You can take it down to 1 hp if you like, or 100,000 if you like. The relationships hold based on generally accepted motive power curves.



Forgive me, but I never claimed the AC6000 was from that era.

Since you brought up steam locomotive power curves, we might as well use real ones. Doing a simple curve fitting from the C&O's own scatter plot on the H8 shows a maximum DBHP of 6,600. Every steam locomotive ever made - including the Class A, and the Big Boy, and every 4-8-4 - produced far less HP then the Allegheny. From NS own data, they were never able to get more than 4,400 HP out of the J 611 in excursion service--and that was after a total rebuild. That's the facts, I am not playing a game.
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Posted by selector on Thursday, May 29, 2008 9:29 PM
GP40-2, please check your private messages.
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Posted by AnthonyV on Thursday, May 29, 2008 9:31 PM
 Bucyrus wrote:
 MichaelSol wrote:
 AnthonyV wrote:

Based on the inherent power characteristics of each type of locomotive, the Diesel should always pull at least as much tonnage as a steam engine over the entire practical speed range for a given maximum dbhp.

Anthony V.

This is exactly the opposite of what is clearly shown by the published and generally accepted TE/HP curves for the respective motive power types. And those do, in fact, define the "inherent power characteristics."

 

Michael,

If I may parse Anthony's statement, the following conclusion could be drawn from it, according to my interpretation of it: 

If a steam locomotive and a diesel locomotive each producing say 4000 hp and pulling enough tonnage in identical trains on identical track to limit the top speed to say 40 mph; the tonnage of the two trains would be identical.  Is that not true?

When you say that the truth is opposite of what Anthony said, I am not sure what you mean by opposite.     

 What I am saying is that the Diesel will outpull the equivalent hp steam engine over the entire practical range that freight trains operate, except at the point that the horsepower of each type is equivalent.

Performance data for the UP Big Boy are as follows (I don't know the source -I've had it laying around for several years):

Speed, MPH       dbhp                TE, lb

0                         0                  131,000

10                 3307                   124,000

20                 5227                    98,000

30                 6000                    75,000

40                 6080                    57,000

50                 5733                    43,000

60                 5120                    32,000

Diesel power totaling 6080 dbhp will outperform the Big Boy over the entire speed range except at 40 mph, the point where the power of each is equal.  The Diesels will pull more tonnage at all other speeds or the same tonnage at higher speeds.

 

Anthony V.

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Posted by Anonymous on Thursday, May 29, 2008 9:36 PM
 MichaelSol wrote:
 Bucyrus wrote:

What does the last column of figures on the right indicate?

Those are the hp required to move the train; irrespective of the motive power. As train speed increases, friction, particularly air resistance, increases, requiring more horsepower to overcome the friction. You can see that it is an expensive proposition to move a train at 70 mph.

I don't understand the meaning of the last column in relation to the rest of the table.  I thought the table compared two locomotives starting an identical train, accelerating it to 70 mph, and recording the horsepower produced by each locomotive as the speed increased.  However, if it takes 25,927 hp to move the train at 70 mph, then neither locomotive will get it anywhere near 70 mph.  So then what exactly is being compared in the performance of the two locomotives?

For instance, what is the steam locomotive doing when it is producing 7,677 hp compared to what it is doing when it producing 8,129 hp?

This is in reference to your table as follows:

 

MPH      Diesel-electric         Steam       HP  needed
5    4,2781,806         307
10    5,1333,613         743
15    5,6004,516      1,239
20    5,6005,600      1,839
25    5,6006,323      2,562
30    5,6007,226      3,426
35    5,6007,677      4,446
40    5,6007,948      5,641
45    5,6008,129      7,028
50    5,6008,310      8,624
55    5,6008,400     10,447
60    5,6008,310     12,513
65    5,6008,219     14,840
70    5,6008,129     17,445

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Posted by MichaelSol on Thursday, May 29, 2008 9:41 PM

 GP40-2 wrote:

Forgive me, but I never claimed the AC6000 was from that era.

But you want to compare it with a single unit C&O unit of 50 years ago.


Since you brought up steam locomotive power curves, we might as well use real ones. Doing a simple curve fitting from the C&O's own scatter plot on the H8 shows a maximum DBHP of 6,600. Every steam locomotive ever made - including the Class A, and the Big Boy, and every 4-8-4 - produced far less HP then the Allegheny. From NS own data, they were never able to get more than 4,400 HP out of the J 611 in excursion service--and that was after a total rebuild. That's the facts, I am not playing a game.

You don't get it. The power curves represent equivalent weight on drivers. You might have two steam engines and three diesel-electrics with a total of 5600 hp at 20 mph. It doesn't necessarily mean it is from one unit.

And, because of that, it doesn't matter if you don't think a modern steam engine couldn't generate 8,500 hp at 60 mph. Two Northerns could. An equivalent weight of diesels can't. The fact is that "a" steam engine generates more horsepower at a higher speed than a diesel-electric locomotive with equivalent weight on the drivers. You can back the hp back. You can increase it. You can double the number of locomotives. You can do anything you please, but for so long as the weight on the drivers is equivalent, the relationship holds true with increasing speed.

 

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Posted by jmlaboda on Thursday, May 29, 2008 9:41 PM
 MichaelSol wrote:

 GP40-2 wrote:

That's interesting MichaelSol. What specific steam locomotive did you use to produce the 8,400 HP? The C&O's H8 Allegheny - the most powerful steam locomotive ever built - "only" produced 6,600 DBHP at 45-50 MPH, with a DECLINING HP curve above 50 MPH.

And which Diesel-electric generated 5,600 hp in that era? Missed that, didn't you? Actually, no, it is consistent that you like to mix up modern machines with 50 year old machines, and claim a revelation. It's part of your game. The chart is on a comparable horsepower basis. You can take it down to 1 hp if you like, or 100,000 if you like. The relationships hold based on generally accepted motive power curves.

For that matter what about today's diesels.  Yah, we can all talk about AC6000ACs and the SD90MACs but the fact remains that they are very few in number, and with the railroads still buying less powerful locomotives and not the 60000 HP beasts what does that indeed say about them?  If they were the answer that they were suppose to have been why are they not being built for North American use???

As far as moderation goes, I sure do hope that they do a better job than editting Kalmbach magazines or we are all in trouble...

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Posted by MichaelSol on Thursday, May 29, 2008 9:51 PM
 Bucyrus wrote:

I don't understand the meaning of the last column in relation to the rest of the table.  I thought the table compared two locomotives starting an identical train, accelerating it to 70 mph, and recording the horsepower produced by each locomotive as the speed increased.  However, if it takes 25,927 hp to move the train at 70 mph, then neither locomotive will get it anywhere near 70 mph.  So then what exactly is being compared in the performance of the two locomotives?

That is correct, the Diesel-electric cannot move the train past 39 miles per hour. The Steam engine can continue to accelerate the identical train to approximatly 49 miles per hour. This is why I mentioned that, to actually get to 70 mph, you would have to add more units of each, but because the Steam engine generates the greater horsepower at that speed, the need for more Steam units is lower than the number of Diesel-electric units.  The capital and operating cost of reaching that speed is substantially lower, therefore, with Steam because that speed operates in a very favorable portion of the power curve, whereas with Diesel-electrics it is a very unfavorable portion of the power curve.

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Posted by MichaelSol on Thursday, May 29, 2008 9:59 PM
 AnthonyV wrote:

 What I am saying is that the Diesel will outpull the equivalent hp steam engine over the entire practical range that freight trains operate, except at the point that the horsepower of each type is equivalent.

Since the Steam engine hp changes throughout the operating range, there cannot, by definition, be an "equivalent hp" throughout that range. You are making something up here that isn't true to go in some usual direction.

At 19 mph, a reciprocating Steam engine that is putting out 5600 hp will generate 50% more TE than a Diesel-electric locomotive(s) generating 5600 hp at that speed. Again, this is using equivalent weight on the drivers, which is a measurable constant throughout the operating range and therefore comparable in a way that your numbers are not.

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Posted by AnthonyV on Thursday, May 29, 2008 10:23 PM
 MichaelSol wrote:
 AnthonyV wrote:

 What I am saying is that the Diesel will outpull the equivalent hp steam engine over the entire practical range that freight trains operate, except at the point that the horsepower of each type is equivalent.

Since the Steam engine hp changes throughout the operating range, there cannot, by definition, be an "equivalent hp" throughout that range. You are making something up here that isn't true to go in some usual direction.

At 19 mph, a reciprocating Steam engine that is putting out 5600 hp will generate 50% more TE than a Diesel-electric locomotive(s) generating 5600 hp at that speed. Again, equivalent weight on the drivers, which is a measurable constant throughout the operating range and therefore comparable in a way that your numbers are not.

I'm not making anything up.  Each locomotive type can be characterized by its nominal horsepower rating.  The Big Boy can be characterized as a 6000 hp machine even though this occurs over a very small portion of its operating range.  Diesels rated 6000 dbhp (either single or in multiples) produce this power over almost their entire operating range except at low speeds, a subject that has been discussed previously.

Therefore, steam locomotive performance can equal the Diesel's only at a single point for equivalent nominal horsepower.

I think the thing that is made up is the concept of equal weight on drivers.  It is irrelevant.

Anthony V.

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Posted by selector on Thursday, May 29, 2008 10:32 PM
How can it be irrelevant when it is so highly contributory to the over tractive effort?  And how do you account for the disparity in absolute performance characteristics at any given speed, except for where they cross?  One's a horse and the other's a mule.  Both good at what they do.  But the steam engine, even now, gets the hearty nod because it is so cheap to run by comparison.  One crew riding 6000 hp can do what two or three MU'd units do now with one crew.  Cleaner, cheaper to run, even though the crewing is identical.
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Posted by MichaelSol on Thursday, May 29, 2008 10:34 PM
 AnthonyV wrote:

I think the thing that is made up is the concept of equal weight on drivers.  It is irrelevant.

Anthony V.

Saving this one for future reference.

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Posted by GP40-2 on Thursday, May 29, 2008 10:44 PM
AnthonyV,

Please check your PM concerning this subject.

Thanks, GP40-2
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Posted by AnthonyV on Thursday, May 29, 2008 10:50 PM

 selector wrote:
How can it be irrelevant when it is so highly contributory to the over tractive effort?  And how do you account for the disparity in absolute performance characteristics at any given speed, except for where they cross?  One's a horse and the other's a mule.  Both good at what they do.  But the steam engine, even now, gets the hearty nod because it is so cheap to run by comparison.  One crew riding 6000 hp can do what two or three MU'd units do now with one crew.  Cleaner, cheaper to run, even though the crewing is identical.

I am not saying that the weight on drivers is irrelevant to locomotive performance.  What I am saying is that comparing steam and Diesel on the basis of equal weight on drivers is irrelevant.  Steam locomotives only had a fraction of their total weight on drivers while Diesels had all their(with some exceptions) on drivers.  Using equivalent weight on drivers as a basis for comparison artificially penalizes the Diesel.

Anthony V. 

 

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Posted by Anonymous on Thursday, May 29, 2008 10:57 PM

 selector wrote:
How can it be irrelevant when it is so highly contributory to the over tractive effort?  And how do you account for the disparity in absolute performance characteristics at any given speed, except for where they cross?  One's a horse and the other's a mule.  Both good at what they do.  But the steam engine, even now, gets the hearty nod because it is so cheap to run by comparison.  One crew riding 6000 hp can do what two or three MU'd units do now with one crew.  Cleaner, cheaper to run, even though the crewing is identical.

I think the relevance of weight on drivers in this thread depends on its relevance to what we are discussing at any particular point.  Certainly it is relevant to locomotive performance in general.  So is the number of drivers, maximum horsepower available, and transmission ability to vary torque versus RPM.  However, in these last couple pages, I thought we were comparing how steam compares to diesel in terms of developing horsepower at various speeds.  I don't see what the weight on drivers has to do with that.

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Posted by MichaelSol on Thursday, May 29, 2008 11:09 PM
 Bucyrus wrote:

I think the relevance of weight on drivers in this thread depends on its relevance to what we are discussing at any particular point.  Certainly it is relevant to locomotive performance in general.  So is the number of drivers, maximum horsepower available, and transmission ability to vary torque versus RPM.  However, in these last couple pages, I thought we were comparing how steam compares to diesel in terms of developing horsepower at various speeds.  I don't see what the weight on drivers has to do with that.

The horsepower requirements are developed from tractive effort, which is, in fact, directly related to the weight on the drivers. Ultimately, it has everything to do with performing the calculations regarding horsepower, which is why I "marked" the earlier comment that thinks the whole idea of "weight on the drivers" is "just made up" or 'irrelevant".

The forumula is: HP=TE*Speed/375

 

 

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Posted by jmlaboda on Thursday, May 29, 2008 11:13 PM

 AnthonyV wrote:
Steam locomotives only had a fraction of their total weight on drivers while Diesels had all their(with some exceptions) on drivers.  Using equivalent weight on drivers as a basis for comparison artificially penalizes the Diesel.

Its a tractive effort thing... since diesel-electrics these days have all their weight on their drivers, be they 4- or 6-axle it seems to me that it would penalize steam more than diesel, since not all the combined weight is ever applied to a steamer, except it be a steam storage or tank locomotive.

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Posted by selector on Thursday, May 29, 2008 11:15 PM

Okay, fellas, I'm just trying to make sense of this, and please don't take my statements as implying that I am absolute in my understanding.  I suppose my next approach to making sense of all this for Crandell's sake is the following series of questions: is a comparable diesel doing 20 mph while generating 6000 hp (do they?) going to have the tractive effort to apply to a given tonnage hauled that an H-8 would be capable of doing at 20 mph?  Maybe my terms are muddled.  Should I be asking about adhesion and not tractive effort?  Is adhesion good enough in either case that we need only deal with tractive effort?  Will three SD-40's pulling 10,000 tons apply more of their effort to the rails than a single H-8 would at speeds between 5 and 50 mph?  What does Michael's chart suggest and how would any of you counter it with theory expressed in a credible source?

Be gentle.  I bruise easily.

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Posted by MichaelSol on Thursday, May 29, 2008 11:23 PM
 AnthonyV wrote:

I am not saying that the weight on drivers is irrelevant to locomotive performance.  What I am saying is that comparing steam and Diesel on the basis of equal weight on drivers is irrelevant.  Steam locomotives only had a fraction of their total weight on drivers while Diesels had all their(with some exceptions) on drivers.  Using equivalent weight on drivers as a basis for comparison artificially penalizes the Diesel.

Anthony V. 

This is a gem. The weight on the drivers is the weight on the drivers. That's how the power gets to the rail. Ninety per cent of the train is weight "not on the drivers" and doesn't "penalize" the Diesel-electric any more or less than the fact penalizes a Steam engine.

 

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Posted by Anonymous on Thursday, May 29, 2008 11:25 PM
 MichaelSol wrote:
 Bucyrus wrote:

I think the relevance of weight on drivers in this thread depends on its relevance to what we are discussing at any particular point.  Certainly it is relevant to locomotive performance in general.  So is the number of drivers, maximum horsepower available, and transmission ability to vary torque versus RPM.  However, in these last couple pages, I thought we were comparing how steam compares to diesel in terms of developing horsepower at various speeds.  I don't see what the weight on drivers has to do with that.

The horsepower requirements are developed from tractive effort, which is, in fact, directly related to the weight on the drivers. Ultimately, it has everything to do with performing the calculations regarding horsepower, which is why I "marked" the earlier comment that thinks the whole idea of "weight on the drivers" is "just made up" or 'irrelevant".

The forumula is: HP=TE*Speed/375

 

 

I understand what you are saying and how tractive effort relates to horsepower and speed.  But what I have been focusing on is your table about horsepower.  I don't see that the table indicates any relationships about tractive effort even though tractive effort has a relationship to horsepower in locomotive performance.

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Posted by Anonymous on Thursday, May 29, 2008 11:51 PM
 selector wrote:

Okay, fellas, I'm just trying to make sense of this, and please don't take my statements as implying that I am absolute in my understanding.  I suppose my next approach to making sense of all this for Crandell's sake is the following series of questions: is a comparable diesel doing 20 mph while generating 6000 hp (do they?) going to have the tractive effort to apply to a given tonnage hauled that an H-8 would be capable of doing at 20 mph?  Maybe my terms are muddled.  Should I be asking about adhesion and not tractive effort?  Is adhesion good enough in either case that we need only deal with tractive effort?  Will three SD-40's pulling 10,000 tons apply more of their effort to the rails than a single H-8 would at speeds between 5 and 50 mph?  What does Michael's chart suggest and how would any of you counter it with theory expressed in a credible source?

Be gentle.  I bruise easily.

I would explain it this way:  Tractive effort depends on adhesion, which in turn depends on weight on drivers, number of drivers, and the condition of the rails.  Tractive effort also depends on the ability of the locomotive to produce force (in the form of torque) at the drive wheels.  Turning the wheels against the load by the application of torque is called work.  Work performed per unit of time is called horsepower.  Moving the train is the work.  The faster you move it, the more work you accomplish in a given time.  Theoretically a windup clock could develop enough torque to pull a 10,000 ton train, but just not very fast.  I say theoretically because, from a practical standpoint, there would be so much friction in the massive speed reduction that the clock would not be able to overcome it.

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Posted by MichaelSol on Thursday, May 29, 2008 11:51 PM
 Bucyrus wrote:
 MichaelSol wrote:
 Bucyrus wrote:

I think the relevance of weight on drivers in this thread depends on its relevance to what we are discussing at any particular point.  Certainly it is relevant to locomotive performance in general.  So is the number of drivers, maximum horsepower available, and transmission ability to vary torque versus RPM.  However, in these last couple pages, I thought we were comparing how steam compares to diesel in terms of developing horsepower at various speeds.  I don't see what the weight on drivers has to do with that.

The horsepower requirements are developed from tractive effort, which is, in fact, directly related to the weight on the drivers. Ultimately, it has everything to do with performing the calculations regarding horsepower, which is why I "marked" the earlier comment that thinks the whole idea of "weight on the drivers" is "just made up" or 'irrelevant".

The forumula is: HP=TE*Speed/375

I understand what you are saying and how tractive effort relates to horsepower and speed.  But what I have been focusing on is your table about horsepower.  I don't see that the table indicates any relationships about tractive effort even though tractive effort has a relationship to horsepower in locomotive performance.

The Diesel-electric and Steam outputs were generated from published HP tables. The "HP necessary" -- the far right hand column --was generated directly from a TE table, using the equation to generate equivalent horsepower for the simple expedient that the conversation was about Steam's ability to generate horsepower at higher speeds and horsepower and speed seems to offer a more intuitive presentation regarding what the motive power types confront as they attempt to increase the speed of the train. 

A similar table showing only TE would show both motive power types declining in TE; the Diesel-electric declining in output more rapidly than a Steam engine of the same weight on the drivers, and generally with considerably greater TE output at the higher speed, which is consistent with the higher HP output of the Steam engine at the higher speed.

   

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