New ES44C4 (A1A-A1A) Locomotive

Yeah, not exactly a rip-roaring success like the MPI commuter locos... and I still find it comical that they have rear ditch lights!

FCP503 wrote:I remain sceptical of the "cost savings" notion that has been presented.

You mean you think the cost savings over AC-motor C-Cs won't be great enough to justify A1A-A1As? Or, you mean BNSF must think the A1A-A1A has some other advantage beside the cost savings? If so, what ?

FCP503 wrote:I also find it hard to believe that 8 paws on the rails will ever be as good as 12.

No one thinks they are. Maybe somebody thinks 8 AC-powered wheels can match 12 DC-powered wheels-- or maybe somebody thinks they can come close enough, 99% of the time. The success or failure of the experiment is going to depend on that 1%.

timz wrote:You mean you think the cost savings over AC-motor C-Cs won't be great enough to justify A1A-A1As?

I do not believe that lower initial investment cost outweighs the potential shortcomings of the design.

timz wrote:Or, you mean BNSF must think the A1A-A1A has some other advantage beside the cost savings? If so, what ?

I am really hoping that I am wrong and that there will be some performance bonus here that has not as yet been deduced on this forum. It would be an an engineering acheivement if these units perform as well of better than expected.

timz wrote:No one thinks they are. Maybe somebody thinks 8 AC-powered wheels can match 12 DC-powered wheels-- or maybe somebody thinks they can come close enough, 99% of the time. The success or failure of the experiment is going to depend on that 1%.

My concern is that these units will not work as advertised. If these units can't acheive their performance targets then the net cost for operating these locos will be higher, and not lower than a conventional six motor unit. I also beleive that any purchaser needs to consider how this loco will be used during it's entire lifespan, and not just the first five years when the unit has super high availability.

I also said to any one that would listen at the time that I thought that the 6000hp locos from EMD and GE would never work as advertised either. It was stated at the time that that to replace two 3000hp units with one 6000hp unit, that a 6000hp units had to be TWICE as reliable. That was a goal that could never realistically be acheived. Additionally no matter how good the wheel slip systems employed, 24 wheels will have better adhesion than 12. It was easy for me to say that at the time because DOUBLING reliability in one one or two design generations is almost never acheived.

It seems that ALL highpowered B-B units are very slippery by nature. (Why I asked about wether any B-B AC drive units were in use) The above posts should be food for thought.

Never forget that putting power in the railhead is the name of the game. All locomotive operators need to win that game to be cost effective. I would not want to be the exec at BNSF in charge of this program.

FCP503 wrote:I do not believe that lower initial investment cost outweighs the potential shortcomings of the design.

How much lower is it?

FCP503 wrote:I am really hoping that I am wrong and that there will be some performance bonus here...

Performance bonus for subtracting two motors? How could there be?

It seems that ALL highpowered B-B units are very slippery by nature. (Why I asked about wether any B-B AC drive units were in use) The above posts should be food for thought.

Never forget that putting power in the railhead is the name of the game. All locomotive operators need to win that game to be cost effective. I would not want to be the exec at BNSF in charge of this program.

Maybe if someone who has run a say Dash 9 (a DC model) and then ran a Evo in AC trim would share a good story as to the differences in adhesion/power/traction on roughly the same loco wiht the same HP, with the variable being AC compared to DC, and if the AC models are more slippery than their DC counterparts with heavy freight locos.

In my own personal experience in passenger, with both electric and diesel DC and AC- ALP 44, which is DC, and ALP 46, which is AC - that the slipperyness is MUCH more on the AC motor than the DC. I have always figured its the way that the power is being put to the rail, in that the power being used by the traction motors tends to decrease as speeds increase with DC (at least in Amps), while the AC tends to hold steady/increase as the speeds increase. (the needle all the way up at the "power" line)

This is only a "seat of the pants" and "by the eyes" observation, of actually running the locos and watching the load/ammeters.

Same with the diesels too - a Geep (DC) will load less as it is accelorating, and when it gets up to 80 plus MPH, in notch 8, its only drawing 300-400 amps at the traction motor. While a PL42 will keep building power and at 80mph under full throttle its putting 100 percent power to the wheels.

It seems to me that there are two types of wheel slip that B-B AC powered locos deal with - starting off - tractive effort, and then wheel creep and then slip, while at speed, or accelerating. Ive noticed at least on the PL42s and the ALP46s that it happens about 53 or so MPH. Where on a DC powered Geep, (or even ALP44 DC electric loco) that that wheel slip/creep at speed happens much less often, and usually only under bad rail conditions, namely because the TMs are getting less current.

I apologize as im not real good with the technical info as to what it does why it does it, I have forgotten and purged all that from my brain but I just know what the loco does and what I have noticed might cause it, and how to deal with it.

But getting back to these freight units, I wonder if the slipperyness of the ACs in 4 axle trim in passenger service will spill over to freight in the A1As, and I can see that being a problem if you are sailing along at speed on a nice, high speed intermodal train, uphill and in the rain, and then the loco gets some nice wheel creep and then slip (and then regains traction) around 50 or 60mph. Can you say pulled drawbar?

MEC407 wrote:

FCP503 wrote:Outside of the two AC passenger units EMD made (and received no orders for) have any other B-B AC drive diesels been made in North America?

Yes:

EMD DE30AC
EMD DM30AC
GE P32AC-DM

And EMD produced 2 (IIRC) experimental F59PHAC units which were tested by Amtrak as well....

Not to get too far off topic but it does seem that there may be some potential applications for AC Drive technology in North American BB freight locomotives for switching work. There a several European manufacturers building 4 axle AC motored switchers and at least one company in the US; Republic Locomotive, is offering an AC propulsion Industrial "Critter" unit. The idea is that a lower HP prime mover coupled to an AC drive system will result in a locomotive that pull like a bigger engine. Republic claims that it's little 500 HP AC drive switcher produces the same tractive effort as a 1000/1200 HP EMD SW unit and uses significantly less fuel to do it. Purchasing costs are higher, O.C but IINM AC traction motors are cheaper to maintin..

v8interceptor wrote:

FCP503 wrote:Outside of the two AC passenger units EMD made (and received no orders for) have any other B-B AC drive diesels been made in North America?

And EMD produced 2 (IIRC) experimental F59PHAC units which were tested by Amtrak as well....

Those were "the two AC passenger units EMD made" that FCP503 was referring to.

I had a question about a theory I have. I am NO electrical engineer, but I thought something they might have been trying to do was a concept like the Chrysler 300c. It can switch between 4 and 8 cylinders as needed. Example :when getting up to speed it uses all 8, but then at highway speed it shuts 4 off, and uses only 4. While it has been said elsewhere that AC traction motors can be heavily loaded without worry (while DC traction motors cannot) I think that by incorporating this concept it will take care of the "dead axle" concerns some of you have had. (dragging around a dead axle per wheel set). HOWEVER, this concept can also be applied to heavy hauling slow freights too. Use all of the motors to get going, or to push/pull grades, and when they are no longer needed, it goes into A1As. (I believe Gensets do this?, but with the actual diesel motors, NOT the traction motors/inverters). Thoughts?

OK, everyone take a deep breath a minute and hold on.

Why is everyone so freaked out about idler axles on locomotives? There have been locomotives with idler axles about as long as there have been locomotives.

Why is everyone so freaked out about high horsepower four axle diesel-electric locomotives? We've been making this comparison since the U25 and the differences in application DICTATED by design are well understood.

Why is everyone so freaked out about the amount of horsepower in four driving axles? The U36B was announced as available roughly 1970, which means we've had roughly 900 HP/axle diesel-electric locomotives available for almost FORTY YEARS. With AC motors and modern slip control there's no need to imagine that this cannot be made to work.

Why is everyone so freaked out about A1A trucks? Did every train ever hauled by E-units, ALCO-GE passenger units, F-M Eries all just slip and stall to a standstill in every station, on every grade? No, they did not.

Let's look at the facts. Not every train needs to be able to drag along wide open below 20 MPH. This is why Santa Fe kept buying DC units after AC traction motors were on the scene. Higher priority trains running long distances at high speeds don't need the extra weight of six motors, or the extra cost. This is EXACTLY THE SAME THING that was all gone through ALREADY in the 1960's during the "Great Six Axle Debate" launched by ACL, and ALCO with the C-628 as a response to some complaints/problems with the high horsepower four-axle units of the day (primarily the heavily promoted GE U25B.) And guess what? Railroads like the New York Central that didn't need six-axle units STILL DID NOT BUY ANY SIX AXLE UNITS.

Further, these aren't power drills. They're not binary, on-off machines. Anyone recall EMD's Drag Duty Performance Control? How about GE's Automatic Power Matching? Yes... you do NOT need to develop full rated horsepower at low speeds, and in fact cannot so you make the locomotive derate itself at low speeds. See? Very easy to understand. At a speed where full power is not going to cause continuous slip, the locomotive allows full rated power. You might imagine this on a long-distance priority stack train where four or five 4000 HP units are running at 50 MPH. You don't need six axles per unit with AC drive to get 4000 HP on the rails at that speed.

GE probably is in the best position to offer this design alteration, since it still to the best of my knowledge uses one inverter per axle. This cuts inverter cost by 1/3 on a locomotive. EMD with one inverter per truck saves little except the cost of traction motors, but GE saves that too.

Let's do a little math here. Let's suppose for the sake of argument that the new A1A units weigh about 400,000 lbs max. That would give you about 267,000 lbs on drivers - roughly that of the old GP-35, U25B up through the GP-40. But with new adhesion control and the AC motors that's fine. If we guess at about 30 percent adhesion we get a starting effort of roughly 90,000 lbs per unit, rounding up a bit. We're assuming that the equalization is such that the weight is equal on all axles -- it may NOT be. I'm also assuming the adhesion figure there. Now just glancing at the old B40-8 with a continuous figure of about 69,000 lbs at about 19 MPH, we see that there is much room for improvement on even this impressive (for a four-axle unit) figure with the new six-axle, four-motor AC drive unit. Yes, there may be cost savings yet uncalculated in using the same trucks for example minus some parts as well.

The previous paragraph is almost ALL assumption, and although I hate assumptions, it is necessary here to get the point across. Further, in some other forums there's been some other freaking out over "why are there no new four axle units." Well, this is a step toward that. But the units still have six axles and won't cause increased damage on the track structure, which no railroad wants.

Let's wait to flip until we actually have something concrete -- such as the FIRST press release, eh?

-Will Davis

PS: As to Kf's comment about motor cutout, BLH did that with the last AS-616's in the mid-50's to allow higher voltage to the four motors remaining above the cutout speed of 37 MPH. However, that was a byproduct of the Westinghouse equipment's max voltage and permanent series-parallel connections; today, the voltage range is much higher and there's no need to drop axles to get motor speed.

The big motive for this, at least if our speculations on this board are right, is reduction in purchase price due to not having as many motors. (There's alsoa weight saving: the two motors omitted probably weigh about three tons each, and the inverter's to go with them must weigh something... hold the total train weight constant and every ton you eliminate from the locomotive you can add to the payload.) How much of a savings is it? Not having any information about this model, I can only try some (possibly obsolete) rules of thumb.

(A) It used to be said that a diesel electric locomotive was, in terms of cost, very roughly one third diesel engine, one third "locomotive mechanical portion" (carbody, trucks, airbrakes...) and one third electrical gear. Maybe -- the electrical part being where the biggest technological innovations have been -- the elctricals would now be a FAT one third. Now, the ES44C4 gets rid of one third of the traction motors and one third of the inverters but still has the whole generator. Reduction in cost: maybe 10%, but I'd be surprised to learn it was that much,

(B) Back in the 1970s I remember it being said (a propos of SCL's purchase of new GE-built road slugs ("MATEs") to go with their U36B) that a C-C unit tended to be about 20% more expensive than the corresponding B-B: a corresponding A1A-A1A ought, therefore, to be somewhere between these. Split the difference (assume, in the absence of any more precise estimate, that the A1A-A1A is 10% more expensive than the B-B) and we get the A1A-A1A being about 8.7% less expensive than the C-C.

So maybe -- until we hear more -- we should think in terms of the cost-savings on an ES44C4, relative to an ES44AC, as being approximately in the neighborhood of something like roughly 9%. Which doesn't, perhaps, sound all THAT impressive. But remember, BNSF is a company that can, without making big headlines, buy 350 locomotives in one year! At which point even small-seeming savings begin to add up.

Allen Hazen wrote:The big motive for this, at least if our speculations on this board are right, is reduction in purchase price due to not having as many motors. (There's also a weight saving: the two motors omitted probably weigh about three tons each, and the inverter's to go with them must weigh something... hold the total train weight constant and every ton you eliminate from the locomotive you can add to the payload.)

Also, as per the news piece, the reduction in weight should result in greater fuel economy.

I don't think any of us are 'freaking out' over this but, in a non-stop parade of safety cab equipped 4Khp locomotives, a slight variation will garner attention. Even though this change is not apparent to the casual observer, it's a good sign to see a mechanical department thinking outside the box. Remember, "If you want a new idea, read an old book."

Why don't more (any) US manufacturers go with a geared motor system, like many French locomotives had? They've worked with monomotor trucks driving two sets of wheels - seems like it wouldn't be a big stretch for two motors to drive three axles, even steered ones.

mtuandrew wrote:Why don't more (any) US manufacturers go with a geared motor system, like many French locomotives had? They've worked with monomotor trucks driving two sets of wheels - seems like it wouldn't be a big stretch for two motors to drive three axles, even steered ones.

As a future engineer once said, "The more they overthink the plumbing, the easier it is to stop up the drain." The current setup of one traction motor, one traction motor pinion, one bull gear and one axle is simple and effective.

On the other end of the spectrum, it's interesting that there has not been a modern day attempt toward gearless traction; the axle becomes the motor armature. This was found on the MILW Bi-Polars and NYC S-motors. To the best of my knowledge, this has not been tried with three-phase induction.

mtuandrew wrote:Why don't more (any) US manufacturers go with a geared motor system, like many French locomotives had? They've worked with monomotor trucks driving two sets of wheels - seems like it wouldn't be a big stretch for two motors to drive three axles, even steered ones.

For risk of straying off topic, but it deserves to be mentioned,

the NJT ALP46 has a quill type drive, similar in concept to the GG1s.

http://www.railway-technical.com/drives.shtml

The ALP46 (a B-B AC traction locomotive) is based on the German DB 101 mentioned in the article.

That article in the link gives a good description on the various types of traction drives in the world today, including both AC and DC traction motors