wsherrick wrote: Thanks for all of your effort to post these graphs and other statistics. I know from years of experience and by empirical observation of the locomotives I have operated about how any given steam locomotive of equal weight to a diesel, blows the diesel away after you get it above 5 MPH or so. I know that diesels have supposedly more tractive effort at starting than the steam engine with approx the same weight on the drivers, but what you find out when you run the diesels is that they often can't take advantage of this tractive effort because of the power to weight ratio. EMD's are especially bad in this area. The diesel easily slips at starting because there is not simply enough weight on the driving wheels to take advantage of it. Often times one has to have the engine pull against the independent brake, peg the Amperes way up into the danger zone and get the train started that way because otherwise the diesel simply can't start the train without excessive slipping or if it gets started can not maintain the pull necessary to keep the train rolling because the tractive effort and horsepower curves drop off so quickly. So often times it takes two engines to pull what is in the theoretical ability of one engine. The steam engine once it gets the train rolling can generally accelerate it and pull it with ease.
Thanks for all of your effort to post these graphs and other statistics. I know from years of experience and by empirical observation of the locomotives I have operated about how any given steam locomotive of equal weight to a diesel, blows the diesel away after you get it above 5 MPH or so. I know that diesels have supposedly more tractive effort at starting than the steam engine with approx the same weight on the drivers, but what you find out when you run the diesels is that they often can't take advantage of this tractive effort because of the power to weight ratio. EMD's are especially bad in this area. The diesel easily slips at starting because there is not simply enough weight on the driving wheels to take advantage of it. Often times one has to have the engine pull against the independent brake, peg the Amperes way up into the danger zone and get the train started that way because otherwise the diesel simply can't start the train without excessive slipping or if it gets started can not maintain the pull necessary to keep the train rolling because the tractive effort and horsepower curves drop off so quickly. So often times it takes two engines to pull what is in the theoretical ability of one engine. The steam engine once it gets the train rolling can generally accelerate it and pull it with ease.
I seem to remember reading the comparison that, "A diesel can start any train it can pull and a steam engine can pull any train it can start."
I'm interested if any shortlines that operate steam tourist locomotives (who was it that bought those Chinese made locomotives a few years back?) will find them more economical than their diesels...
Also, wasn't the Sierra Railroad experimenting with an almost all biodiesel fueled fleet? Any updates on their experiences, in light of recent petroleum fuel costs?
How about R.J Corman? They have several coal hauling operations and they just took delivery of a QJ...It's an interesting thought.......
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
ExBNSF Manager wrote:It wont ever happen. With every major shipper getting a tax cut on fuel and shipping having a fuel surcharge that is past on to the consumers, there is no reason why they would care. Haven't you ever wondered why diesel is higher than unleaded now? It is what is supporting the US economy every time you go by a candy bar. 99% of the US market relies on products that are shipped on diesel surcharge. No reason for corporate to make a move for another fuel. The only thing that is hitting them now is the EPA and California for polution.
With every major shipper getting a tax cut on fuel and shipping having a fuel surcharge that is past on to the consumers, there is no reason why they would care. Haven't you ever wondered why diesel is higher than unleaded now? It is what is supporting the US economy every time you go by a candy bar. 99% of the US market relies on products that are shipped on diesel surcharge. No reason for corporate to make a move for another fuel. The only thing that is hitting them now is the EPA and California for polution.
I don't mean to single your comment out. Don't take it personally. You are only illustrating the totally block headed view that is guiding the entire transportation industry. So basically as long as the transporters can gouge shippers and then the shippers can get tax breaks because they are being gouged, then that's the way the World should rotate and no other ideas or progress can be made until the industry is forced to. Much like when the Railroads were forced to adopt air brakes and automatic couplers. The industry then couldn't see that these innovations would save them millions in lost productivity, loss due to wrecks derailments and loss of life. Today the mindset is still the same. "We're not gonna do anything until we have to," As I stated earlier in this thread, innovative thinking is punished in the rail management world. I found out about that the hard way. Young men with ideas get hammered for, "rocking the boat." Regional railroads, Terminal Railroads and many short lines can't benefit from fuel surcharges and it is from there that the change will come I believe. And I don't find the evidence that shippers are compliant with the whole fuel surcharge idea as the Congressional Record shows. A year ago the Congress found that the Class Ones were overcharging for fuel and a limit has been placed on that. The pressure to reign in exorbitant fuel surcharges will only increase as time wears on. And if the Democrats get their rail re-regulation bill off the ground, forget it.
rrandb wrote:The fact that most electricity is produced by coal and not diesel tells which is most cost effective period.
There are a few caveats here.
Number One: Almost all steam plants make use of condensers to reduce the back pressure to about 1 psi absolute (about 14 psi of vacuum at sea level). This helps enourmously with thermal efficiency. Even then, typical thermal efficiencies for modern coal plants are around 33% as compared to 60% for the latest generation of combined cycle plants.
Number Two: The furnaces on a coal fired plant are quite large, not practical to shrink down to locomotive size (though a gasifier may help). The primary heat transfer mechanism in the furnace is radiation - where a locomotive makes greater use of convection (though radiation dominates in the firebox and combustion chamber.
Number Three: A power plant has a lot more room for pollution controls than a locomotive - to be fair this is also true for diesels, there's not much room to put a catalytic converter on a diesel locomotive.
MichaelSol wrote: erikem wrote: For road power, steam's advantage when the need was for horsepower as opposed to tractive effort, where many of the new AC locomotives are being used where the need is for tractive effort. If I recall correctly, two 6 axle AC locomotives can generate as much starting tractive effort as three Big Boys. For machines with the same weight on the drivers, Steam exceeded the tractive effort output of a Diesel-electric above 6-7 mph. Above 19 mph a Steam engine exceeded the Diesel-electric in both tractive effort and horsepower and the margin of both increased as speed increased.In the range 0-7 mph, the Diesel-electric could generate more tractive effort, but the rate of loss in its ability to do so was very high. In that same range, the Steam engine generated more TE than it did at higher speeds, as with the Diesel-electric, but the rate of loss in the ability to generate Tractive Effort was much lower.Because of that, at 30 mph, the Diesel-electric had lost 82% of the TE it generated at 2 mph, while the Steam engine lost only 20% of the TE it generated at 2 mph, and exceeded the TE output of the Diesel-electric by a substantial margin. Notably, at 30 mph the Steam engine is generating 100% more Tractive Effort than the Diesel-electric machine.At 30 mph, the Steam engine also exceeded the hp of the Diesel-electric, by 20%, and continued to generate increasing horsepower to 60 mph, exceeding the Diesel-electric by as much as 30-35%.
erikem wrote: For road power, steam's advantage when the need was for horsepower as opposed to tractive effort, where many of the new AC locomotives are being used where the need is for tractive effort. If I recall correctly, two 6 axle AC locomotives can generate as much starting tractive effort as three Big Boys.
For road power, steam's advantage when the need was for horsepower as opposed to tractive effort, where many of the new AC locomotives are being used where the need is for tractive effort. If I recall correctly, two 6 axle AC locomotives can generate as much starting tractive effort as three Big Boys.
For machines with the same weight on the drivers, Steam exceeded the tractive effort output of a Diesel-electric above 6-7 mph. Above 19 mph a Steam engine exceeded the Diesel-electric in both tractive effort and horsepower and the margin of both increased as speed increased.
In the range 0-7 mph, the Diesel-electric could generate more tractive effort, but the rate of loss in its ability to do so was very high. In that same range, the Steam engine generated more TE than it did at higher speeds, as with the Diesel-electric, but the rate of loss in the ability to generate Tractive Effort was much lower.
Because of that, at 30 mph, the Diesel-electric had lost 82% of the TE it generated at 2 mph, while the Steam engine lost only 20% of the TE it generated at 2 mph, and exceeded the TE output of the Diesel-electric by a substantial margin. Notably, at 30 mph the Steam engine is generating 100% more Tractive Effort than the Diesel-electric machine.
At 30 mph, the Steam engine also exceeded the hp of the Diesel-electric, by 20%, and continued to generate increasing horsepower to 60 mph, exceeding the Diesel-electric by as much as 30-35%.
For locomotives pre-dating the EMD super series traction control, the steamers could deliver higher sustained tractive effort for a given weight on the drivers. After that, the diesel's did better. A modern 6 axle AC locomotive can generate a higher continuous tractive effort (at low speeds) than a Big Boy, and weigh about as third as much. A 6,000 HP version will produce almost as much drawbar horsepower as the Big Boy and cost about the same as inflation adjusted price for a Big Boy.
The locomotives with the worst fall-off of drawbar power with speed were the electrics running off a DC electrification - the operating characteristics of a DC series motor mandated that the current decrease as speed went up for a constant supply voltage (hence a drop in power). One way of getting around that was field shunting.
erikem wrote: A power plant has a lot more room for pollution controls than a locomotive - to be fair this is also true for diesels, there's not much room to put a catalytic converter on a diesel locomotive.
Ah, but the catalytic converters are required on Diesel-electrics after 2017. There is a reason the requirement is out there so far, but presently, the converter is the only way to bring the diesel engine into compliance with emission standards. This will reduce the economic efficiency of the Diesel-electric locomotive.
On the other hand, the fluidized bed method of coal combustion has proven successful at bringing the combustion efficiency of coal up to 13%, and reducing emissions that TVA built its most recent plant without the catalytic converters -- the first one -- and it is burning cleaner than the remainder of its plants -- all with the catalytic converters.
...Michael, I believe the catalytic converters increased the efficiency of the automotive engines {gasoline}, back about 1975. Their use allowed other polution removing means to be lessened on engines promoting the ability to retune said engines for better performance and economy. Said polition was then "cleaned up" by the converters before passing out into the atmosphere.
Wouldn't the effect on diesel engines be similar.....?
Quentin
MichaelSol wrote: erikem wrote: A power plant has a lot more room for pollution controls than a locomotive - to be fair this is also true for diesels, there's not much room to put a catalytic converter on a diesel locomotive. Ah, but the catalytic converters are required on Diesel-electrics after 2017. There is a reason the requirement is out there so far, but presently, the converter is the only way to bring the diesel engine into compliance with emission standards. This will reduce the economic efficiency of the Diesel-electric locomotive.On the other hand, the fluidized bed method of coal combustion has proven successful at bringing the combustion efficiency of coal up to 13%, and reducing emissions that TVA built its most recent plant without the catalytic converters -- the first one -- and it is burning cleaner than the remainder of its plants -- all with the catalytic converters.
Catalytic converters are much smaller, lighter, less expensive to purchase and maintain than are scrubbers. Catalytic converters do not produce waste solids that require disposal as do scrubbers and fluid bed combustion systems. And at the end of thier life catalytic converters are valuable as scrap, scrubbers are not.
Fluid bed combustion requires two feed systems. So you must not only carry your fuel, you have to carry the lime (usually) that will react with the sulfur. Fluid beds are much larger than normal locomotive combustion chambers. The fluidization requires that a lot of energy be expended before you even get combustion so the overall energy efficiency is lower because of the parasitic loads. And you have to have a huge dust collection system, which is expensive to buy and maintain and requires more energy to operate. And at the end of the day not only must you replenish the coal and lime, you must remove and dispose of the calcium sulfate which contains significant amounts of mercury and other hazardous substances.
Modelcar wrote: ...Michael, I believe the catalytic converters increased the efficiency of the automotive engines {gasoline}, back about 1975. Their use allowed other pollution removing means to be lessened on engines promoting the ability to retune said engines for better performance and economy. Said pollution was then "cleaned up" by the converters before passing out into the atmosphere.Wouldn't the effect on diesel engines be similar.....?
...Michael, I believe the catalytic converters increased the efficiency of the automotive engines {gasoline}, back about 1975. Their use allowed other pollution removing means to be lessened on engines promoting the ability to retune said engines for better performance and economy. Said pollution was then "cleaned up" by the converters before passing out into the atmosphere.
My understanding, which is very limited in this area, is that catalytic converters are in the exhaust cycle -- after the engine energy is delivered to the powertrain, and so cannot contribute to energy conversion efficiency except in a negative fashion. Since the effectiveness of the converter depends on a variety of fuel conditions, the converter also "controls" -- through some more electronics -- certain engine functions to minimize combustion byproducts -- and this is almost always at the sacrifice of engine efficiency.
The trick has been to develop catalytic converters that reduce emissions while minimizing the effect on engine efficiency, and these are often characterized as "increasing engine efficiency" which they do, sort of, compared to older pollution control equipment, including previous catalytic converter models, but not compared to an engine which is designed solely to maximize fuel efficiency.
Figures I recall seeing -- and its been quite a while and this could be completely haywire -- reported fuel efficiency losses as high as 10%, in addition to the cost of the catalytic converter which, for production automobiles, can run as high as 5-8% of the retail cost of the automobile. These are expensive additions to equipment, and add their own maintenance costs as well as reducing fuel efficiency.
On automobiles, my limited understanding is that a typical catalytic converter doesn't measure up to the typical engine life, and must be replaced at least once, often twice, during the economic service life of a typical automotive engine. Today's converters may have a better life span, but what that might mean in 2017 when Diesel-electric locomotives will be required to have them is, well, a long way off ... for good reason ...
And this was the quantum leap for coal combustion from the standpoint of Steam locomotion: discovering a straightforward combustion technology -- fluidized bed -- that doubled efficiency and minimized emissions to something below what the very best and most expensive catalytic converter technology can achieve.
For those who contribute without reading the whole thread. The Porta Firebox is a simple application based on the nature of combustion. It decreases the consumption of coal of an average of 25 to 30%. On the Red Devil, The Argentina and other locomotives fitted with this firebox consistently show these savings in fuel. Under optimal conditions the Red Devil showed a decrease of 65% in fuel consumption. Also the emissions from the locomotive is well below what is required by the EPA. There is no need for scrubbers or any other extra stuff to be added to the maintenance and first cost of the locomotive. Diesels will NEVER be able to meet these standards and the added equipment required to make them come somewhere close will only make the first cost of the unit more and increase the already high expense in maintenance.
erikem wrote: MichaelSol wrote: erikem wrote: For road power, steam's advantage when the need was for horsepower as opposed to tractive effort, where many of the new AC locomotives are being used where the need is for tractive effort. If I recall correctly, two 6 axle AC locomotives can generate as much starting tractive effort as three Big Boys. For machines with the same weight on the drivers, Steam exceeded the tractive effort output of a Diesel-electric above 6-7 mph. Above 19 mph a Steam engine exceeded the Diesel-electric in both tractive effort and horsepower and the margin of both increased as speed increased.In the range 0-7 mph, the Diesel-electric could generate more tractive effort, but the rate of loss in its ability to do so was very high. In that same range, the Steam engine generated more TE than it did at higher speeds, as with the Diesel-electric, but the rate of loss in the ability to generate Tractive Effort was much lower.Because of that, at 30 mph, the Diesel-electric had lost 82% of the TE it generated at 2 mph, while the Steam engine lost only 20% of the TE it generated at 2 mph, and exceeded the TE output of the Diesel-electric by a substantial margin. Notably, at 30 mph the Steam engine is generating 100% more Tractive Effort than the Diesel-electric machine.At 30 mph, the Steam engine also exceeded the hp of the Diesel-electric, by 20%, and continued to generate increasing horsepower to 60 mph, exceeding the Diesel-electric by as much as 30-35%.For locomotives pre-dating the EMD super series traction control, the steamers could deliver higher sustained tractive effort for a given weight on the drivers. After that, the diesel's did better. A modern 6 axle AC locomotive can generate a higher continuous tractive effort (at low speeds) than a Big Boy, and weigh about as third as much. A 6,000 HP version will produce almost as much drawbar horsepower as the Big Boy and cost about the same as inflation adjusted price for a Big Boy.The locomotives with the worst fall-off of drawbar power with speed were the electrics running off a DC electrification - the operating characteristics of a DC series motor mandated that the current decrease as speed went up for a constant supply voltage (hence a drop in power). One way of getting around that was field shunting.
These six axle AC diesels have the same problem as the others when it comes to the power to weight ratio. The diesel doesn't give the 6000 horsepower until it is in notch 8. Therefore that horsepower isn't available for starting the train. The ability of a locomotive to pull regardless of type depends on how much weight is on the drivers. The diesel doesn't have the weight on the drivers to take advantage of its theoretical tractive effort and thus will slip helplessly when starting in many cases.
Also, if these locomotives are so vastly superior in pulling power and horsepower output then you would see one unit pulling the same tonnage that a Challenger, Big Boy, Class A or other comparable steam locomotive but you don't. You see three of them pulling the same tonnage that the single steam locomotive pulled on a regular basis. One of these diesels can't take a 15,000 ton coal train like a Class A did by itself everyday.
Now we are talking again about steam from a half century ago and comparing them to the newest diesels out there. The modifications done by Chapleon, Porta and Wardale to existing locomotives caused them to double their thermal efficiency, double their horsepower, and cut fuel consumption by astounding amounts. These modifications were done with existing locomotives which greatly limited what could be done within the parameters of the original design. The potential for development of the standard steam locomotive is vast, whereas diesel technology is moribound when comes to increasing performance, fuel economy or anything else for that matter. I know its hard for those who worship at the alter of EMD to accept this but it's the truth. All the stats, graphs, references given here overwhelmingly support this claim. I am reminded of a remark made by David Wardale when he was over here working on the 614 back in 1985. He said a simple modification of 614's valves and steam passages would give the 4-8-4 more horsepower than the Big Boy. That remark has stayed with me over the years as an insight of what potential lies dormant in the steam locomotive.
Michael....I'm simply making the comparison {on automobile gasoline engines}, and getting back to the era right before the typical catalytic converters were installed, fuel economy {and performance}, were at a low point.....1973-74 time bracket. The emission controls that were in place {and required}, were reducing capable performance of the auto engines. So my statement then, intends to relate...performance and economy were advanced from the low point when the catalytic converters were put into production and made part of the powertrain package and replaced the anti pollution methods previously in place.
I agree, catalytic converters are not going to increase performance and economy compared to an engine with no polution equipment installed.
I just checked the 5at project site and they have just posted one of Wardales exhaustive works on the theory and practice of modern steam. For those of you who have an engineering bent and can understand pages of Calculus ( I only took 2 semesters of it in college) These papers have complete diagrams and calculations for the Gas Combuster Firebox, Lempor exhausts, boiler specs, in short the whole ball of wax where he lays out the probabilities and potiential for new steam. I'll try and post a link, I'm not too good at it but here goes;
http://www.5at.co.uk/
(corrected by selector. Just type/paste it, and then immediately hit "enter" on a Windows system.)
wsherrick wrote:These six axle AC diesels have the same problem as the others when it comes to the power to weight ratio. The diesel doesn't give the 6000 horsepower until it is in notch 8. Therefore that horsepower isn't available for starting the train. The ability of a locomotive to pull regardless of type depends on how much weight is on the drivers. The diesel doesn't have the weight on the drivers to take advantage of its theoretical tractive effort...
I've run everything from a 2-8-0 to a Berkshire, mikados, worked on many other steam locomotives, GE U Boats, Most models of EMD's and Alco Diesels. I see these AC locomotives daily and I still don't see a single AC unit pulling the same tonnage that any of the largest steam power and you can't tell me that these units are not slippery devils, so I guess I do know what I'm talking about. I know GP 40, that you have totally imbibed the Diesel kool aid, but that's fine, I also run into people like you everyday as well. No hard feelings there pal. By the way NS and CSX are buying DC motors for the mountainous coal regions for drag service for some reason. I heard that from a CSX employee just this morning as we were discussing this very topic.
PS: I have worked on a Class A.
Al Krug has this to say:
"One night I was running a freight up hill at 7 mph with a Dash 9-44CW on the point. I had previously calculated that we should have gone up the hill at 11 mph, so why were we only doing 7 mph? The rail was slightly frosty. I punched up the loco monitor screen on the computer. It showed that this supposedly 4400 Hp unit was only putting out 2930 HP!!! It had derated to prevent slipping in spite of the sanders being on. So the adhesion factor of this loco at that time was not the touted 36-43% but instead only 22%. The railroad had paid for a 4400 HP locomotive with 36% adhesion but was only getting a 2930 HP locomotive with 22% adhesion. The common SD40-2 would have done as good or better in this situation than the hi-tech wonder. This was not a one time occurrance. I have seen similar performances on many occasions."
"If you haven't been paying attention you might think that the new 6000 HP single unit locos are destined for heavy haul service. True they are all heavy 6 axle units. But that is because the weight is needed to put that 6,000 HP to the rail without slipping. A 6,000 Hp unit that weighs 420,000 lbs and can attain a 43% adhesion factor has an adhesion of 180,600 lbs. The 6,000 Hp diesel engine can deliver that 180,600 lbs of Tractive Effort at a speed of 13 mph. Below that speed you cannot use full throttle on these locos because they will slip. That was for an astounding adhesion factor of 43%. What if they cannot maintain that extreme level of adhesion? What if they "only" get 36%? 36% of 420,000 lbs is 151,200 lbs of TE. The 6000 hp diesel can deliver that TE at 15 mph so the loco cannot operate below 15 mph in full throttle without slipping. At an adhesion factor of 30% the lowest full throttle speed is 18 mph. If the rail is wet or frosty can these modern marvels maintain even a 30% adhesion factor? My experience with 4400 Hp units is a definite no. The C44s often have trouble maintaining 22% adhesion with bad rail conditions. If a 6,000 Hp unit gets down to 22% adhesion it can only operate at full throttle above 24 mph! Thus if you want these behemoths to reliably move your trains over the hills in all kinds of weather you had better dispatch them with trains light enough that they can maintain 24 mph or greater on your steepest hills. That means they are only useful for trains such as intermodals which get a high Hp to tonnage ratio. When it is frosty they won't work on heavy freights or coal or grain trains which routinely pull up the hills at 10-12mph. "
"Modern locos such as SD70MACs and C44s claim adhesion factors of 36 to 43%! They do this by using sophisticated anti-wheelslip circuits. These circuits allow the wheels to spin slightly faster than the rail speed warrants. It is called creep. Strangely enough, a creeping wheel has a higher factor of adhesion than a stationary or rolling wheel. Thus in theory two 6,000 HP SD90s weighing 420,000 lbs each and achieving an adhesion factor of 36% will produce a TE of 302,400 lbs and should pull the train up the hill at 15 mph.
"However, in my experience you cannot count on that 36% adhesion factor in all types of weather and rail conditions. On wet or frosty rail these units slip and you stall. And when you stall you had better set the train airbrakes in a hurry or the train will slide these units back down the hill. On the other hand I have had C44s, SD90s and SD70MACs absolutely astound me with what they are pulling. At times they attain greater than 40% adhesion on dry, sanded, rail. It is that "at times" that concerns me. You cannot count on them to do that reliably time after time. "
Interesting. I can imagine what modern electronic control technology might do for a reciprocating steam engine. On the other hand, maybe I can't: Steam was never my cup of tea. Of course, given that the Diesel-electric was deficient in many ways compared to Steam at the outset, operating costs made the difference. The same logic may hold true today, with the opposite results ....
wsherrick wrote:... CSX are buying DC motors for the mountainous coal regions for drag service for some reason...
MichaelSol wrote:Al Krug has this to say...
Al Krug has this to say...
GP40-2 wrote: MichaelSol wrote: Al Krug has this to say...Al Krug didn't test AC's on the Mountain Sub...I did. Like I said, the figures I gave are from ACTUAL service...What don't you guys understand about ACTUAL...
MichaelSol wrote: Al Krug has this to say...
As regards actual fuel costs today ... right on! Those things actually are important. The best machine in the world is worthless if it costs too much trying to do the job ...
MY aren't we combative! I will answer your question about the Y6b on the B&O's west end when you tell me how often a single AC unit goes over the grade and how much it pulls. Or is it more than one unit at a time? And at what speeds does the AC unit produce this "continous tractive effort," and what speeds do these engines produce these horsepower ratings? Any decent size Northern can produce 4000 horsepower for a wide range of speeds
MichaelSol wrote: GP40-2 wrote: MichaelSol wrote: Al Krug has this to say...Al Krug didn't test AC's on the Mountain Sub...I did. Like I said, the figures I gave are from ACTUAL service...What don't you guys understand about ACTUAL...As regards actual fuel costs today ... right on! Those things actually are important. The best machine in the world is worthless if it costs too much trying to do the job ...
wsherrick wrote: GP40-2 wrote: MichaelSol wrote: Al Krug has this to say...Al Krug didn't test AC's on the Mountain Sub...I did. Like I said, the figures I gave are from ACTUAL service...What don't you guys understand about ACTUAL...MY aren't we combative! I will answer your question about the Y6b on the B&O's west end when you tell me how often a single AC unit goes over the grade and how much it pulls. Or is it more than one unit at a time? And at what speeds does the AC unit produce this "continous tractive effort," and what speeds do these engines produce these horsepower ratings? Any decent size Northern can produce 4000 horsepower for a wide range of speeds
GP40-2 wrote: wsherrick wrote:... CSX are buying DC motors for the mountainous coal regions for drag service for some reason...That is 100% wrong.You still didn't answer my question about the Y and A on the West End...
Your word is as good as the engineer I was talking to, both claims are unsubstantiated so if I goofed by quoting this man, I apologize for all. Now these are the some of the specs for Y6b's and A's and this is the last of this conversation because if we are going to talk about AC/DC units and comparing them to 60 years ago, there needs to be another thread started on it. This thread is about the feasibility of modern steam, its characteristics, design and potential for use TODAY and the future that we are barreling toward.
Class A:
Starting Tractive Effort: 114,000 LBS.
Maximum DRAWBAR horsepower: 5,350 @ 40 MPH
Continuous Drawbar horsepower: 5100 between 24 & 64 MPH
Tonnage Ratings: Williamson to Columbus OH-16,000 t0 18,000 tons @ 15 to 30 MPH.
Time Freight Tonnage: 7,500 Tons @ 64 MPH
Class Y6b:
Starting Tractive Effort: 160,000 pounds, 152,000 continuous TE in compound mode.
Maximum Drawbar Horsepower: 5,600 horsepower @ 25 MPH
Continuous Drawbar Horsepower: 5000-5100 between 17 & 34 MPH
Tonnage Rating for a single Y6b on the 1.6% grade between Gln Lynn and Bluefield Summit is 3900 Tons.
Maximum Rating for 2 Y6b's on the same grade is 10,000 to 11,000 Tons
Source: N&W Records, circa 1950
Another item to look at when comparing a new steam locomotive to a traditional one is what Porta and other call the, "Steam Circut." I don't have the mathmatical skills to go through the formulas about how it works, but maybe some of the engineering types could jump in and help.
What I do know from being a fireman on a hard working locomotive is the draft is of key importance to the performance of the engine. I have had the coal literally sucked off the shovel as the coal was being placed in the fire. It is really neat to see the lumps of coal burst into flame as soon as they leave the shovel and head for the grate, but neat is not always efficient. According to Wardale and others, the front end design of the standard locomotive is hopelessly poor as well as the valves, steam chests and assorted pipes. In this region is where most of the loss of power occurs as the steam is travelling from the boiler to end up chugging up the stack.
The idea is to have the steam pressure in the cylinders as close to that of the boiler as possible, but there is in the best conditions over a fifteen pound loss of steam pressure by the time the steam makes it to the cylinder. It may not sound like a lot but it is a tremendous loss of power. I believe that every (somebody check me on this) five pound loss of pressure in the cylinder translates into a loss of over five tons of piston thrust. That's quite a lot. The idea then is find out where this loss is occurring. Most of it is due to excessive back pressure formed as the piston is trying to force steam out of the exhaust. This back pressure is due to several causes that compound with one another. It has been found that there are three main culprits: Constriction in the steam passages heading in and out of the steam chest, constriction in the dry pipe and super heater headers and worst of all the constriction in the exhaust nozzle.
Porta after many years of experimentation, along with the emerging science of fluid mechanics developed the Lempor exhaust configuration to solve these problems. The standard nozzle is terribly inefficient not only because of back pressure but the fact that exhausting steam blasting out of it under normal conditions accelerates to supersonic speed. This causes a sonic boom inside the smokebox that has a severe negative effect on the draft. This is called, "shock loss," I believe. You hear this when the engine is working at a long cutoff. People love to hear this massive stack talk, but it is evidence of an enormous amount of power loss. The common practice of putting a bridge across the nozzle to increase draft only makes everything worse.
The Lempor is a revolutionary concept like the Gas Combuster Firebox. The Lempor has four exhaust ports that end up in four De Val nozzles. Each exhaust port has a baffle in it called a, Kordina," this creates the,"Kordina Effect." In other words what happens is the Kordina prevents steam from each cylinder combining with the steam from the opposite one and as each pulse of steam exhausts it creates a vacuum to remove any back pressure from the opposite cylinder as it is exhausting. From here the steam en trains the smoke box gasses in a much slower manner and thus is much more efficient. The steam actually en trains the smoke rather than punching through it, also the sonic boom is eliminated. This nozzle and petticoat arrangement also insures an even draft through all of the flues, thus the boiler efficiency is increased by a large margin. The common straight stack doesn't work well with the Lempor and engines that get them get large funnel shaped stacks. Sort of like a Sweeny stack found on many UP locomotives. For the Lempor to work it's best a different configuration in the valves are needed. The entry and exhaust ports must be made larger and as open as possible. The steam chests are also made longer with larger ports. All of these things combined cause a dramatic reduction in back pressure and increase in cylinder efficiency, leading to a doubling of draw bar horsepower for a lot less steam.
Another big benefit of this is a reduction in water consumption of 20% on average. It's amazing to me that you get twice the horsepower and use 80% of the water to do it. These efficiencies that have been measured in rebuilt locomotives would be even more in a new locomotive designed from the ground up.
So now that the UP has put a double Lempor on the Challenger and done extensive firebox and running gear changes. I am excited to see just how much of an increase in horsepower the Challenger will achieve and how much fuel they will be saving. Don't be too surprised if you don't see it on a long double stack train this summer during its testing.
wsherrick wrote: So now that the UP has put a double Lempor on the Challenger and done extensive firebox and running gear changes. I am excited to see just how much of an increase in horsepower the Challenger will achieve and how much fuel they will be saving. Don't be too surprised if you don't see it on a long double stack train this summer during its testing.
MichaelSol wrote: wsherrick wrote: So now that the UP has put a double Lempor on the Challenger and done extensive firebox and running gear changes. I am excited to see just how much of an increase in horsepower the Challenger will achieve and how much fuel they will be saving. Don't be too surprised if you don't see it on a long double stack train this summer during its testing.This sounds more like a research project than maintaining a historic relic ....
Yes, I quite agree. This,"treasured antique," as some put it earlier in this thread, has been significantly altered from its original design at a substantial cost to the company. I'm inclined to believe that this money wasn't spent for the occasional happy excursion.
The other odd thing about this work is the Union Pacific has been extremely secretive about it. Nigel Day is involved and he shut down a discussion about the Challenger in the Railway Preservation News Forum.
This gets into one very controversial aspect of the discussion of steam art advancement. I am all for the scientific and engineering advancement of steam and its reconsideration of use for railroad motive power. I also love the historic age of steam and the diesel era as well. However, I am absolutely opposed to the modernization of historic steam antiques. There is no reason to make these engines capable of moving more tonnage or burning less fuel unless it is in the mind of ones who fail to understand the point of preserving historically authentic antiques.
I have heard all the arguments; that these operators must compromise authenticity for the pragmatism of operating efficiency---and that the upgrades are hidden so the public will never know. And besides, the riding customers are mostly not railfans, and hardly know anything about railroads, let alone steam locomotives.
As I mentioned previously, the Durango & Silverton has been offered strong recommendations to modify their locomotives with GP fireboxes and Lempor exhausts. At this time, they seem inclined to turn down the proposal in favor of addressing the overnight smoke nuisance with scrubbers. At one point Wasatch Railroad Contractors and the Smoke Mitigation Taskforce were both soliciting public input on solutions for the smoke issue. I made it clear to both groups that I was opposed to destroying historical authenticity of the locomotives by radical upgrades in pursuit of efficiency.
Shutdown discussions notwithstanding, hearing that UP has added a Lempor exhaust to their Challenger depresses me.
I guess I don't have a problem with the Lempor ejector nozzle on the UP Challenger.
These locomotives are antiques yes, and they are historical recreations of the heydey of steam, yes as well, but the alternate history in which steam stayed around another 10 years and locomotives got fitted with those ejectors is also part of the history.
Try this analogy. Suppose there was some group of wealthy EAA types who somehow got ahold and restored to flight status a B-36, complete with those monster R-4460 radial piston engines driving pusher props and those outboard jet engines. Suppose some maniacs with time on their hands actually built the Variable Discharge Turbine (VDT) upgrade to the turbo-charging system of those engines that had been planned but never done. Not quite sure what the VDT was, but it seems to be a kind of turbocharger that used the engine exhaust for supplemental jet thrust to the propulsive force of the engine.
If there were some maniacs with enough time and money to do this, I would say, more power to them rather than complain that they are corrupting a one-of-a-kind antique aircraft. Likewise with putting fancy ejectors or firebox systems on the Colorado narrow gauge of the UP Northern or Challenger locomotives. Those systems are all part of the history of steam as they were conceptualized in many cases but not applied.
This is almost like saying, no, don't hot-rod a 1932 flat-head V-8 Ford with chromed carbs, manifold headers, and other performance parts. The 1932 Ford is a priceless antique and the Beach Boys committed sacriledge by memorializing the highly modified Deuce Couple in song.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
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