Is there a web site that will tell you the horsepower rating of different locos?
Website…not that comes to mind…only think I could think of is try googleing “EMD SD90MAC specs.” or something like that and it might work. Otherwise I would recomoned “Field Guide to Modern Diesel Locomotives” by Greg McDonnell. Its published by Kalmbach. Its a really nice book, it tells the HP, model of engine traction motor, etc, and a little history on each type. It had MK, EMD, and GE diesels in it. Its worth every penny to me. Hope that works for ya.
This piqued my curiosity as well. I like big horsepower numbers, but being a car guy too, I am more impressed with torque output as a realistic measure of power. Is there anyplace to find torque ratings?
Not sure about the tourque. The book I said above doesn’t have it listed. As are as trains go…I think tractive effort (measured in pounds) and torque is the same. not 100% however.
Torque really isn’t a relavent measure here.
What???
If prime mover torque isn’t relevent, please inform us what is spinning the main traction alternator to produce electrical current.
I suspect your response will be amusing.
FYI:
GEVO (4400 Traction HP) engine produces 23,550 lbs-ft torque @ 1050 RPM
EMD 710 (4300 Traction HP) engine produces 26,500 lbs-ft torque @ 900 RPM
GE HDL (6000 Traction HP) engine produces 32,100 lbs-ft torque @1050 RPM
Your typical V-6 found a late model car might produce 250 lbs-ft torque.
Well of course torque is important from a physics perspective, don’t be silly, and don’t try and be a smart alec.
However, the poster was asking for torque numbers similar to what one would get for automobile performance. In the case of a Diesel Electric locomotive, Torque doesn’t represent the same thing at all. In fact, a very very brief glance through EMD’s website doesn’t show a single reference to the Torque of any of the 710 product line.
Torque isn’t relevent in the same way and therefore in the context of the question asked, it isn’t a relevent measure.
The Torque of the Engine is such that it will generate the correct power output at the correct RPM
The tractive Effort of a loco is the functional equivelent of torque in a car and that is where the comparison should be made.
Now, I’m sure somewhere you can find the torque numbers and given that we’re talking about Diesels that are so large that you could stuff one or more rat motors in one cylinder (in terms of displacement) those numbers would be impressive, but they aren’t really relevent in the same way.
Blah, Blah, Blah.
Again, if you don’t think the torque of a prime mover isn’t relevent to locomotive proformance, you are clueless. Good thing you don’t actually work in this industry.
Let’s keep the tone a bit more civil, please. If you find that you cannot convince the person with the contrarian view from yours with your words or with documents linked in your message, just agree to disagree and move on. No one gets points or an award for persevering at the cost of civility.
Thanks.
[#ditto]
THANK YOU!
[#ditto]
Is torque inversely proportional to RPM; and/or is there some other reason why the engine with higher horsepower and higher RMP produces less torque than the engine with less horsepower and lower RMP? Thanks very much.
The torque of the prime mover is not measured and doesnt matter, the prime mover only turns the altenators ( which there is 3) this is why there is no torque numbers. the numbers you gave are effort reading of the traction motor in which you ( for your own satisfaction) changed to read in ft. pounds of torque , Ive only seen electric motors rated in horse power units and effort , never torque. Oh and i do work in the industry, and even though i dont study engines like i use to ( cars trucks and motorcycles and locomotives ) I do
Stroke length is an important factor in torque, the EMD engine is slightly longer stroke. But like everything else there are trade-offs. With the longer stroke there is greater stress on bearings, etc.
The 1TB2630 traction motors used in the SD70MAC are rated at 9729 lb-ft. of torque.
I’m sorry this thread got a little heated, but it’s always nice to be courteous even when you disagree.
Of course, Given the double negative in GP40-2’s post, he is unintentionally agreeing with me anyway.
Also thanks to Wabash1 for backing me up.
I will say that even though you typically deal in group ratings, the tractive effort is still the relevent measure. You just don’t need to know the actual value, because that work has been done for you to increase efficency.
We’ve also discussed in other threads how Horsepower relates to speed and so, Tractive effort isn’t the only relevent measure.
That’s continuous, or maximum? What’s the usual gear ratio? SD70MACs use … 42-inch wheels, or what?
Maybe we should start at the beginning.
One would build an engine only to be able to harness it to some sort of machine to do some useful work. The characteristics of the engine (torque/speed curve) need to be known in order to match it to the requirements of the machine.
In the case of a lawnmower, the engine’s design fits a direct drive of the blade. In the case of a chainsaw or leaf blower, a single reduction gear set makes the match.
In the case of an automobile, a transmission with several gear ratios is needed.
In the case of a DE locomotive, the engine is mated to the traction alternator by direct drive. The traction alternator was designed to match the engine’s characteristics, providing an electrical transmission of nearly infinte effective “gear ratios”.
Once the traction alternator is designed to be matched to the engine, the issue of diesel engine torque/speed characteristics is a moot point. For everything “downstream” of the traction alternator, it doesn’t matter what’s making the electricity. As long as the HP is there, the locomtive will perform.
For the greater part of a locomotive’s operational speed range, the performance is strictly governed by HP. So, knowing what the diesel engine’s speed/torque characteristics won’t tell you anything useful about the locomotive’s performance.
You can nit-pick this around the edges all you want.
Thanks for making the point eloquently.
Now im gonna nit pick. is that going forward or backwards. LOL and dare i need to say anything about dynamic???