Alan Robinson wrote:Please check out the information on the latest high speed test of the TGV at http://travel.timesonline.co.uk/tol/life_and_style/travel/article1608769.ece wherein you will notice each of the two powerheads were drawing 19.6 megawatts.
Please check out the information on the latest high speed test of the TGV at http://travel.timesonline.co.uk/tol/life_and_style/travel/article1608769.ece wherein you will notice each of the two powerheads were drawing 19.6 megawatts.
19.6 magawatt: yes, but on 12 motor-axles (2 powerheads with induction motors and one central unit with sychronous motors, now installed on AGV new train).
Please check out the information on the latest high speed test of the TGV at http://travel.timesonline.co.uk/tol/life_and_style/travel/article1608769.ece wherein you will notice each of the two powerheads were drawing 19.6 megawatts. This would be about your 5.2 megawatts, but on each of four axles. This test achieved a sustained speed of 310 miles per hour and a top speed of 353 miles per hour. The powerheads for this test were equipped with larger wheels and everything, locomotives, cars, track, were carefully adjusted. Even the voltage on the overhead wire was raised temporarily. Clearly, this will not be the normal operating speed or conditions.
The power draw of 19.6 megawatts converts to a little over 26,000 horsepower. Not all of this will appear at the rails, but about 90% of it will. Even this works out to about 23,600 horsepower.
Remember, work is force times distance. The force (tractive effort) may be modest, but the distance is large. Also rember that kinetic energy is proportional to the square of the velocity. Double the velocity while keeping the force constant and you require four times as much power. This is why, when looking for horsepower at the rail, it helps to examine high speed locomotives. This is also how a very moderately sized turbojet aircraft engine with a relatively small static thrust of 10,000 pounds or so (equivalent to starting tractive effort) can produce a horsepower of more than 10,000 when operating at cruise speed of 550 to 600 miles per hour.
Alan Robinson wrote:...I'd say the TGV locomotives probably win the test in terms of horsepower at the rail (although there may be others I don't know about), but in a very specialized service. More normal freight service would require much heavier locomotives such as we see in current US diesel electric practice or in earlier heavy steam days.
I'd say the TGV locomotives probably win the test in terms of horsepower at the rail (although there may be others I don't know about), but in a very specialized service. More normal freight service would require much heavier locomotives such as we see in current US diesel electric practice or in earlier heavy steam days.
A TGV-A powerhead has only 5,2 MW on four axles, with 68 t weight and 100 kN starting effort, max. speed 300 km/h (190 mph).
A Prima 6000 has 6 MW with 88 t on 4 axles and develop a starting effort of 320 kN, maximal speed 140 km/h (90 mph).
There were French examples from Alstom, but German examples have more or less the same values.
Note that the values for electrics are given in continuous power. At "high" speed a greater power can be required for a short time (~140 % for 15 min.) , which is not possible for diesels, limited by the engine power.
We are talking about too may different things here. The conversation isn't all that complicated. There is one answer to the question of "most powerful" and that is which locomotive delivers the most horsepower at the rail. All else is fluff.
Now, what do we do with that horsepower is a different matter.
Starting tractive effort is important because you can't pull a train you can't start, but it isn't everything. Suppose I built a multi drive wheeled, one million pound, rock filled sled and then hooked all the drive wheels together (through suitable gearing of course) to a 3 horsepower lawnmower engine. Starting tractive effort would be about 250,000 pounds, but I don't know of any railroad that would want one. Not even for switching.
Starting tractive effort really has little to do with power and is mostly determined by weight on drivers with other influences such as anti-slip technology and factor of adhesion. Simple steam locomotives had a form of anti-slip control known as side rods. All drive wheels were locked together so that one axle couldn't run away. Geared engines had the same advantages. Articulated locomotives didn't as one engine could slip and not the other. They behaved more like double headed locomotives. Steam locomotives tended to be characterized by the ability to pull any train they could start. But how fast? That depended on boiler horsepower, the ability to turn the heat in coal or oil into high pressure, superheated steam. By overfiring, steam locomotives could be overloaded, sometimes to twice their rated boiler horsepower. It affected starting tractive effort not a whit, but it did everything for tractive effort at speed.
Diesel electrics have high starting tractive effort available IF THEY HAVE ENOUGH WEIGHT ON THE DRIVERS to use what they can produce. Early diesels were generally underpowered for their weight and were not so limited. Modern diesels are more likely to be weight limited (as was most steam) but some of this is made up for by anti-slip technology and synchronous AC drive systems that limit slip as with the side rods of a steam engine. All axles are forced to turn at the same rate.
Any electric drive system, either diesel electric, gas turbine electric or straight electric has two tractive effort limits. One is the starting, or short term, rating. This is the maximum current limit of the motors and controls combined with the gear ratio to produce torque at the rail. It is available for a short time only before something overheats. This limit is large, but it can only be used if there is enough weight on drivers to keep the locomotive from slipping.
The continuous tractive effort is the limit the locomotive can produce continuously without overheating the traction system. There is a minimum speed where this tractive effort can be maintained for any given locomotive. At any speed below this, the continuous tractive effort stays the same. The power from the prime mover (diesel or turbine) or the power from the overhead (electric) must be limited as train speed falls below this speed to avoid destruction of the traction gear. So, a well designed locomotive for normal purposes will usually have the continuous tractive effort located at the same operating point the prime mover reaches maximum power output. Above this speed, tractive effort for a typical diesel or turbine falls because the prime mover can't generate additional power to maintain both tractive effort and speed, too. (The product of tractive effort and train speed is the power at the rails, and must be less than the prime mover's power, as diesels and gas turbines can't be overloaded.) These characteristics combine in diesel electric and gas turbine locomitives to give the ability to start a train the locomotive can't necessarily pull.
Many straight electric passenger locomotives have been designed so there is no starting tractive effort limitation. The locomotive slips due to lack of weight before the continuous tractive effort limit set by the electrical gear is reached. This would be done because for passenger service, horsepower at high speed is what counts. Yes, there had to be enough starting tractive effort to start the train (seldom a problem for high speed service, as trains are short and light) and the required tractive effort increases as train speed goes up due to higher air and rolling resistance. But it usually takes plain old horsepower to move a really high speed train, not tractive effort. Witness the French TGV high speed test recently where a pair of locomotives each produced about 25,000 horsepower. They would be worthless for moving freight, not enough weight and not enough tractive effort, but they could really fly. Another example was the Hudson type 4-6-4. Often less starting tractive effort than the Pacific 4-6-2 they replaced, but lot's more horsepower at speed. Again, not much of a freight engine.
Powerful seems to be used commonly to describe starting tractive effort and effective limit of adhesion. Powerful in that sense should not be confused with power. It is the horsepower that produces tractive effort inversely proportional to the speed and limited by adhesion. Power must be controlled at low speeds to avoid tractive effort exceeding adhesion, around 25% weight on drivers, resulting in wheel slip.
As I recall, the GG1 and SD70ACe have roughly the same horsepower. The difference is the significantly greater weight on drivers and wheel slip control of the SD70ACe that gives greater starting tractive effort. This allows starting and moving a much "heavier" train, a combination of weight, journal, and track modulous factors, at low speeds; but it will not attain more than 13 mph where horsepower-generated tractive effort falls below maximum adhesion. You can get a more exact number with the fundamental engineering formula Tractive Effort=308xRated Hp/Mph (the better efficiency of a modern locomotive will make some small difference). Above 18 mph, assuming 4300hp for both, there is no difference in performance with the same smaller train.
It takes 7.7 hours to travel 100 miles at 13 mph; and 5.6 hours at a continuous 18 mph without delays in route. This does not account for grades that adds 20 lbs lifting resistance per ton per each percent rise. Only a train a third the size of the one that could be started by an SD70ACe could attain 40 mph and take only 2.5 hours for 100 miles, discounting grades and delays in route.
Take the same heavy train that could be started by one SD70ACe and add two more like units combining for 12,900 hp and you can make 40 mph over the road and deliver the load before you turn grey. What good is the 321,000 lb starting tractive effort when you have only 99,300 lbs tractive effort at 40 mph? Three GG1s have more than enough tractive effort to start the same train and still make 40 mph. Three SD70ACe's = three GG1's.
Would you consider an 8,800 hp, 215,000 lb electric locomotive with only 53,600 lbs starting tractive effort to be less powerful? It would take two such units to start the same heavy train as a lone SD70ACe. However, only two electrics would be needed to haul the train at 50 mph instead of only at 40 mph for three SD70ACe's.
The UP three-unit (cab-traction control, turbine-generator, and tender) 8,500 hp gas-turbines were the all-time highest rated horsepower single locomotive in the U. S. until the Acela power cars, basically underemployed TGV's.
Stevo3751 wrote:The only problem with the turbines were that they used just as much fuel idling as they would while operating.
Not quite true - the 4500HP turbines burned 450 gal/hr at full throttle and something like 200 gal/hr at idle. You weren't completely off the mark as a 4400 HP diesel burns a bit over 200 gal/hr in run 8.
We're comparing apples and oranges. The electrics can draw on a humungous amount of energy produced miles away by a turbine and generator the size of a city block, burning a ton of coal every few seconds. They're only half a locomotive anyway - the lower half. Power distribution being equal, the electrics should pull the drawbars out of almost any deiesel.
Best to compare the SD70 to other self-contained locos - in looks it beats them all and I'm a shallow railfan that likes to look primarily at beautiful engines. Yes, yes, the SD70 beats them all!
SUPERMAN
Al - in - Stockton
Neither the PCBs nor the truck frame cracks were the death knell for the GG1s. The cracks were a long time problem and were fixed by welding and stress relieving. They could have gone on forever like that. You reset the fatigue live by heating the castings up in an oven. Cast couplers and other draft equipment pieces go thought this now as part of being reclaimed.
The GG1s were running on mineral oil, not Pyranol at the end, much like the E44s, Jersey Arrows and Silverlinters. There was still a problem with residuals in the transformers, so spills were still reportable.
What killed them was cost of ownership, performance and looming change in catenary power (which only partly happened).
AEM7s and E60s were more powerful, simpler and (supposed to be) faster.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
CNW 6000 wrote:Well why don't we just settle this discussion and make up 2 trains that have identical weights & lengths. We'll hook up an SD70ACe to one and the GG-1 to the other. We'll time them and monitor speeds and train control performance.
If the GG-1 was that great...wouldn't they still be in use?
Wouldn't straight-electric freight engines be rampant if they were that great?
I think that the bottom line is that for its time and even after the GG1 was a truely awsome locomotive. It is sad that the final steam locomotives didn't get to live out their natural service lives so they could be compared in this same manner. Just another example that shows $ are more important than raw performance.
See one of the 3 powerful biggest one-body locomotive: the Alstom-Datong version:
More information:
http://www.railcolor.be/international/viewtopic.php?f=5&t=23
blade wrote:the big boys were pretty masssive and powerful at 4-8-8-4 wheel arrangement.
Very massive: YES 541 t with tender.
Powerful? With only 4,3 MW as a 80t electric BoBo!
The power of a diesel-electric locomotive is limitetd by the power of diesel engine built in!
The maximal power at wheelrim is approximately 30% of the nominal power at engine output axle.
On an electric engine, you can for a short time request 150% of the nominal power, which is not possible with diesel locomotives.
For people wich can read french, please use followink link (only the figure is in english):
http://documents.epfl.ch/users/a/al/allenbac/www/TF49.htm
select "Thermique ou electrique" : comparison between electric and diesel-electric locomotives withe same weight and same mechanical part.
The most powerful single body locomotives will run in China next year (or yet in 2008?): 9,6 MW at wheelrims on CoCo! Three different series are now in building phase by 3 different pairs of constructors.
Jean-Marc, Switzerland
As I see it the question hasn't really been answered. I see the SD70ACE being compared to the GG1. I assume that the SD70ACE is the most powerful diesel (I admit, I haven't followed that aspect of diesel technology) since it is used in the comparison, but is the GG1 really the pinnacle of brute electric locomotive power? I refuse to believe that in 65 years something more powerful hasn't come along. What about the Toasters? Aren't they rated at 7k HP? That is almost double the GG1 and higher HP than even the DD40.
I envision that the spirit of the question is similar to that of the world's strongest man competition. Just keep on adding weight until one drops out.
Frisken wrote: Probably it is the capital investment that's the mayor hurdle these days, not seen any calculations on it but would probably pay itself in a couple of decades however not sure anyone want to make that sort of investment. Not seen any figures, probably also needs a minimum amount of freight before it really becomes profitable. However that is just looking at tons/mile carried there are ofc other factors as proximity to cheap &reliable electric power along the line. Trackside maintanence is somewhat increased with the catenary and ofc also the electrical equipment associated with it. Also the cost of building your own power grid would probably put a dent into the economy aspect of things.The formula for deciding wether to switch from diesel to electrics would look something like: electrics bill + catenary and support eq maintanence bill + loan repayments with intrest on new cat over 40 years + electric locomotives + maint on electric locomotives for 40 years IF this is bigger then the cost of new diesels + diesel maintenance for 40 years + diesel fuel for 40 years then you probably shouldn't electrify said strech of rail. (Never seen any such figures thrown around so ...) The prices are probably hard to say but fuel beeing the expensive part for diesels and catenary system the most expensive one for electrics, a electric locomotive would probably be cheaper then a diesel locomotive of the same size, however don't quote me on that Electrification is widely used in the rest of the world however the "diesel salesmen" probably stopped any such developments in the US. Might have been short-term profits aswell stopping it, don't know for sure. However I've always felt that short term profits and a major capital biz as railroading is isn't really a good match is it? In response to Railway Man: with the big capital investments needed to electrify you have got to have the money on hand which I bet railroads like CN or UP might have at least partially or you got to borrow money, either of those options could make your short term profits drop (money on hand probably means they are working to produce more money for you already or if you borrow you put further expenses to the balance sheet and no new incomes) which would make shareholders annoyed and it would ofc also be detrimental on the short term in the stock market, further reducing your odds at good extensions on loans etc for the major investment you have made. Thus I'm saying no major Railroad would be willing to do this. It would be a major "green" publicity thing and the green lobby would applaud it probably but financially it would at first be a economical nightmare.
Probably it is the capital investment that's the mayor hurdle these days, not seen any calculations on it but would probably pay itself in a couple of decades however not sure anyone want to make that sort of investment. Not seen any figures, probably also needs a minimum amount of freight before it really becomes profitable.
However that is just looking at tons/mile carried there are ofc other factors as proximity to cheap &reliable electric power along the line.
Trackside maintanence is somewhat increased with the catenary and ofc also the electrical equipment associated with it. Also the cost of building your own power grid would probably put a dent into the economy aspect of things.
The formula for deciding wether to switch from diesel to electrics would look something like: electrics bill + catenary and support eq maintanence bill + loan repayments with intrest on new cat over 40 years + electric locomotives + maint on electric locomotives for 40 years IF this is bigger then the cost of new diesels + diesel maintenance for 40 years + diesel fuel for 40 years
then you probably shouldn't electrify said strech of rail. (Never seen any such figures thrown around so ...)
The prices are probably hard to say but fuel beeing the expensive part for diesels and catenary system the most expensive one for electrics, a electric locomotive would probably be cheaper then a diesel locomotive of the same size, however don't quote me on that
Electrification is widely used in the rest of the world however the "diesel salesmen" probably stopped any such developments in the US. Might have been short-term profits aswell stopping it, don't know for sure. However I've always felt that short term profits and a major capital biz as railroading is isn't really a good match is it?
In response to Railway Man: with the big capital investments needed to electrify you have got to have the money on hand which I bet railroads like CN or UP might have at least partially or you got to borrow money, either of those options could make your short term profits drop (money on hand probably means they are working to produce more money for you already or if you borrow you put further expenses to the balance sheet and no new incomes) which would make shareholders annoyed and it would ofc also be detrimental on the short term in the stock market, further reducing your odds at good extensions on loans etc for the major investment you have made. Thus I'm saying no major Railroad would be willing to do this. It would be a major "green" publicity thing and the green lobby would applaud it probably but financially it would at first be a economical nightmare.
Well I thought I had answered some of those questions already and I really hate quote:ing myself but well it was a rather huge post, and I don't blame you for not reading it all through. Some things I could ofc clarify.
First I didn't want to write in plain text that the US probably has a too crappy powergrid for electrification but now I've done that aswell
And on the Maintanance issue ... well there isn't much about it. Costs would ofc be slightly higher for maint but about having ppl placed on remote locations etc, well if that was the case then there probably already is ppl placed there and as such they are already needed and already beeing payed for. Catenerary (sp?) has a very long lifespan and if nothing happens outside the ordinary (de-railings etc) then its just a streched piece of copper wire. And its beeing constantly polished from below by carbon all day.
Some of the regular MOW crews ofc need High Voltage Educations, and a couple of ppl handling refueling of diesels are probably out of work and could be re-educated and some additions to the regular MOW train as a over head wire access car. And the optical inspection vehicle (usually used for track inspections) probably needs a new video camera pointing upwards looking at the OH-wire aswell. But this would ofc be a minor cost.
Well examples of green power is probably unessacary but Hydropower is one, windpower probably could be used if you could smooth things over with the help of the local power grid (see previous note on US Power Grid ) when the wind doesn't produce enough power. Nuclear is ofc another option if the power usage motivates it. Its cost efficent for sure. One other thing is that even if you build your own Nuclear plant / hydro damms / wind power farm the obvious advantage is ofc that the cost is almost a constant (or at least not as much affected by the oil price) which is not the current case with fuel prices which seems to fluctate heavily over time, on the other hand you could probably buy 40 years worth of fuel to make sure you pay the same price for the fuel for the next 40 years, this is essentially what you would be doing if you where to build your own Power plant of any kind. Intrest rates is then the major player here instead of fuel rates
I'm not 100% sure electrification is a solution to anything atm. However raised fuel prices could probably be offset by it. And sitting on your hands probably won't produce anything results. Decreasing pollution to cope with new demands in pollution legislation, which at least some states seems intrested in raising the bar on (probably those without many coal power plants)
I would love to do a comparison but any real numbers on this is hard to come by. A Euro vs US comparison is also hard since here Axle loads are lighter and what I've found so far not even the swedish Ore traffic @30 metric ton / axle comes close to US axle-load limits of roughly 32.8 metric ton / axle. The extra axle load makes it hard to do a comparison between them in terms of efficency.
Say for instant that CSX decided to electrify ( right) all thier major mainlines and build power generation for it. If this is somewhere around 65% of thier total traffic and fuel usage, That would reduce thier fuel bill with roughly 750 Million dollars leaving those money to be put into paying of thier latest and probably world-record sized loan, so what does 750 million dollars in intrest and downpayments over the next 40 years give us then ? Well according to the formula
a = K n * p/100 ( 1+ p/100) n - 1
K n = 750 * (
Europe is significantly smaller then the US and has much newer infrastructure (due to a certain world war destroying most of the old stuff)
The cost to electrify the transcon for instance would be astronomical. And lets not forget that the US already has an electrical generation and transmission issue. So it's not just the capital costs for the railroads, but the capital costs to build the power generation and transmission lines. And what kind of green generation plants will they use? Nuclear power is billions and billions per station. It would be an interesting Chicken and egg issue if they built coal and the green movement would have kittens.
Even the increased cost of MOW, because you'll need to have more crews stationed in remote locations. I can't even begin to imagine.
So no, it's not as simple as railroads not willing to shell out the capital. As if they don't already spend billions maintaining their infrastructure.
Well there was one railroad operating a large Electric system however they had managment hellbent on destroying thier own railroad ... double maintanence posts in book keeping, renting their own cars from others. Showing fantasy earnings by totally ignoring track maintanence etc etc. Yeah you know the one.
Some streches that would have enough traffic and pops into my head is NS from Pennsylvania to Cleveland and on to Toledo & Chicago, Probably the CSX line parralleling it from Cleveland to Chicago also has enough traffic to warrant electrification. In the East probably UP from Chicago to Ogden, maybe UP:s streches in southern California into AZ and on to Texas, BNSF:s line through Southern Calf through AZ and on to St L. Down South Jacksonville,FL -> Manchester, GA on CSX also probably has enough traffic to warrant electrification. NS:s strech from Macon GA to Cincinatti, OH (maybe all the way to earlier named Cleveland -> chicago route however traffic is slower the last part there) would probably also have enough traffic. However that is just looking at tons/mile carried there are ofc other factors as proximity to cheap &reliable electric power along the line.
Back in the Steam days switching to Electrics would probably cut maintanence in half(have heard numbers as low as 10%) and number of locomotives needed cut down to 1/3 of the steam figure. Trackside maintanence is somewhat increased with the catenary and ofc also the electrical equipment associated with it. Also the cost of building your own power grid would probably put a dent into the economy aspect of things.
And please stop comparing GG-1:s (a 1930:s cutting edge locomotive) with a SD70ACe (a 1990:s cutting edge diesel) Electrics also has anti-slip and such features these days (even 1940:s designs had early variations of that here in Sweden) GG-1 where excellent machines with low maintanance and all, probably lower then a SD70ACe even ... however Amtrak decided to "upgrade" to 25kV on the Eastern Corridor and GG-1:s got thier transformers made for 11,25kV filled with cement (might be one or two left but still no OH to run under with correct Voltage) so your purposed test will probably never be.
Ok ok I guess this is a boring post ... congratz you at least read this far down! Then I probably didn't wasted your time too much then then!
Greetings Hans from Sweden
Frisken wrote:[In reference to electrification of freight railroads]: But since capital investment isn't a big thing for US railroads of today I'm guessing this is something we'll never see.
[In reference to electrification of freight railroads]: But since capital investment isn't a big thing for US railroads of today I'm guessing this is something we'll never see.
Not trying to hijack the thread, and perhaps something got lost in translation, but could you explain this for me, please?
RWM
Correct-- because they cost $. Doesn't mean they can't pull.
On a 1000-ton train the GG1 will beat the SD70-- on the level, anyway. On a 12000-ton train the SD70 will win.
Well why don't we just settle this discussion and make up 2 trains that have identical weights & lengths. We'll hook up an SD70ACe to one and the GG-1 to the other. We'll time them and monitor speeds and train control performance. If there's any GG-1s that run anyways...
If the GG-1 was that great...wouldn't they still be in use? Wouldn't straight-electric freight engines be rampant if they were that great? Other than AM(mostly on)TRAK who else in the US uses straight-electric locos? I think that they aren't used for a reason.
Dan
Could we please compare it to a "modern" or at least something built at the same time as the ACe:s ?
I suggest the Swedish Iore which is a 6-axle Bombardier TRAXX-concept Electric AC 3ph traction motor electric locomotive. All data here is for 1 unit not 2 as they are coupled in pairs I don't see the point in complicating things.
Max Tractive Effort 132k lbs (600kN)
Weight 396832 lbs (180 metric Tons)
Top speed 49 mph (80 km/h) However when pulling 8600 metric ton ore trains they have a top speed of 60 km/h or 37 mph due to brake limitations.
HP: 7241 HP (5400kW)
I guess its not really comparable since axle loads are somewhat diffrent in the US and over here in Europe. 30 metric ton per axle here and around 33 metric ton per axle in the US.
IF a US railroad company for some reason ?(skyrocketing fuel costs, electricity prices down low ,copper cheaper than ever etc etc) would ever electrify I'm guessing GE or someone else would build something even more powerful and specific for the US market. That is something I would personally like to see. But since capital investment isn't a big thing for US railroads of today I'm guessing this is something we'll never see.
Greetings from Hans from Sweden
JayPotter wrote:In response to Javier's question, all of the figures that I cited were derived from the basic formula that "adhesion" is the percent of locomotive weight that the unit's adhesion-management system can convert into tractive effort. So, for example, an SD70ACe that, according to EMD's figures, weighs 408K pounds and produces 191K pounds of TE would have an adhesion factor of 46.8% (i.e. 191 divided by 408) when producing that TE. One reason that TE-related calculations become confusing is the concept of the "starting TE" figure (i.e. in this instance, 191K). That figure isn't the maximum TE that an SD70ACe is mechanically capable of producing. It's a software-imposed upper limit that's intended primarily to prevent excessive mechanical stress. If (1) that limitation is removed; (2) rail conditions are extremely favorable; and (3) the unit needs, because of train weight, to produce more than 191K TE; then (4) the unit will produce more than 191K TE. I generally find it more informative to refer to graphs of TE-versus-speed than to perform actual TE calculations.
In response to Javier's question, all of the figures that I cited were derived from the basic formula that "adhesion" is the percent of locomotive weight that the unit's adhesion-management system can convert into tractive effort. So, for example, an SD70ACe that, according to EMD's figures, weighs 408K pounds and produces 191K pounds of TE would have an adhesion factor of 46.8% (i.e. 191 divided by 408) when producing that TE. One reason that TE-related calculations become confusing is the concept of the "starting TE" figure (i.e. in this instance, 191K). That figure isn't the maximum TE that an SD70ACe is mechanically capable of producing. It's a software-imposed upper limit that's intended primarily to prevent excessive mechanical stress. If (1) that limitation is removed; (2) rail conditions are extremely favorable; and (3) the unit needs, because of train weight, to produce more than 191K TE; then (4) the unit will produce more than 191K TE. I generally find it more informative to refer to graphs of TE-versus-speed than to perform actual TE calculations.
JayPotter:
Thanks for the information.
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