After looking at the GM10 locomotive, I’m thinking that 34 years later General Electric should be able to produce a 15,000 hp locomotive using an ES44AC platform. One question I have would be the pantograph, could a single pantograph handle the equivalent of 15,000 hp, or would it be necessary to use two pantographs? The other question regards transferring power to another locomotive. If the equivalent of 4500 hp was being fed the the traction motors of an adjoining ES44AC, could this be handled by a detachable cable, or would something more substantial (a power bus?) be required between the locomotives?
And where is the market for such a beast? Seems to me that the European manufacturers have that end of the locomotive market well covered…I know the IORE locmotives built for a Swedish Iron ore line by Bombardier are actually joined two joined units with separate pantographs. IINM, these are the most powerful electric freight locomotives currently operating:
The Chinese have several series of Co-Co electrics rated at 9600Kw (12,860hp) that have more power than the Bombardier built IORE electrics. The Chinese locomotives were built with help from the European manufacturers.
Your could handle the power with a cable if the voltage is high enough.
The issue is not so much one of jumper cable vs. bus bar connecting two units as whether the electrical system (catenary, substations, etc.) could support the current draw. South Shore ran into this problem when it first began running unit trains in the mid-1960’s.
That’s a big problem with low voltage DC systems, it still plagues the Dutch railway system to this day. Voltage times the the Amperage equals the Power. Higher Voltage requires better insulation, higher Amperage requires a larger conductor wire, and/or bar, and more or larger contacts. Better quality insulation is an easier route than larger cabling. For the US I would recommend locomotives designed to run under both 25Kv and 50Kv. Use the highest voltage in rural areas to allow long distances between substations, use the 25Kv in metro areas where you have many overbridges and such to simplify the insulation and protection.
First, a couple of pieces of information about the ES44AC of today and yesterday’s GM10B …
GE’s AC traction motor (generally known as the “GEB13” motor) is limited to 1000 horsepower. It was originally developed by GE back in 1993 with the 6000 horsepower 6-motor AC6000 locomotive in mind … GE would use one common AC motor for the 4400 HP AC4400 and also for the 6000 HP AC6000.
Therefore, even though an “electric” ES44AC could theoretically draw much more than its rated (engine-produced) 4400 HP from overhead wires, the AC motors underneath are limited to only 6000 HP.
The GM10B used very-large DC motors which were frame-suspended … actually hung up inside the locomotive underframe and protruding down into the truck frames.
Even if there was a freight railroad in the US with 25,000 or 50,000 volt AC overhead power … I see little practical use for a 6-axle 15,000 HP electric locomotive. It would be essentially grossly overpowered. Why? Because you can’t put that much horsepower down to the rails and consistently use it at the rails in contemporary US freight railroading. Can you put 15,000 HP down to 6-sets of wheels? Yes. But typially only for extremely high-speed low-tonnage applications. The Swiss, for example, have 10,000 HP 6-axle electric freight locomotives, and they are used on trains over the Alps and on Swiss-version unit trains (in Switzerland, a “unit train” typically consists of twenty-or-so covered hopper cars carrying cement … roughly a 2000 ton train … in the western US, railroads regularly move 135-to-145 car unit coal trains grossing over 20,000 tons. Why do European railroads have such high-power electric locomotives? One word answer: Speed. In Europe, railroads are (1) passenger movers and (2) freight movers particularly at night when most people aren’t traveling.
The other practical limitation to your "15,000 HP
Hmmm…Do you know that as an absolute fact, or are you just guessing based on the AC6000s 6000 nominal traction horsepower rating?
Rainhilltrial, thanks for the information.
So GE could probably build a 15,000 electric freight locomotive, but only 6000 hp would be usable. Presumably it would be feasible to flank such a locomotive with modified ES44ACs, each drawing the equivalent of 4500 hp, thus using the 15,000 hp? I’ll guess this would cost less than buying 3 5000 hp electrics for a mainline electrification, but there would be a loss in flexiblity.
What is your definition of “usable”, and what makes you think 6000 HP would be the limit?
I really don’t know, I’m just a nutty railfan. My definition of usable would be for freight service at speeds up to 70 mph on a mainline (say BNSF San Bernardino to Galesburg). Obviously the traction motors on an ES44C4 can handle at least 1100 hp each. Can you share any of your knowledge on those motors? Could three of them use 4400 hp if one traction motor was not operable?
As mentioned earlier, adhesion is the great limiting factor to putting 15000 HP (continuous?) on one C-C frame. Consider the VGN EL-2b of 1948: rated at 6800 continuous horsepower, two units with eight traction motors each, at a time when a 1500 HP B-B was a standard road diesel locomotive. Amtrak’s AEM7’s were rated at 7000 HP on 4 axles, but they were built for speed, not tonnage.
May I take this to mean you are unaware of the Black Mesa & Lake Powell RR, and the Deseret & Western RR, both of which are freight only and are electrified at 50Kv?
I do agree with you that a 15,000hp electric is highly unlikely for US railroads if they electrified, but I could readily see them bump the current 4400hp up to say the 6000hp range. This would be useful on Intermodal trains, particularly with DPU.
1600 - 1700 HP max continuous duty, 2000+ HP short term rating per motor.
Thanks!
Yes, the Harmony HXD3B units by Bombardier/Dalian are a whopping 12,860 Hp. Wow! It is mind boggling to think how they accomplished that. GE talks about developing an electric, but as you can see, between the Harmony, Bombardier IORE, and others, the competition is fierce. Not to mention Bombardier has a fleet of Traxx series all over the European continent, and a gigantic factory in Germany.
As it appears that north american railroads using 6000hp diesel units are dropping them (UP, CSX, CP with GE AC6000 or SD90MACS, I mean SD90 and not SD9043), I hardly imagine that electric units of the same power could be used one of these days in the US, had the electrified freight railroads (BM&LP, Deseret & Western) the need to renew their fleet.
Dom
Given that the primary problems with the HDL AC6000CW’s(BTW, last I read CSX was rebuilding,not retiring theirs) and 265 engined SD90MAC-Hs were with the diesel prime movers themselves I don’t think the comparison makes a lot of sense…
The coal haulers you mention currently operate 6,000 HP GE E60C locomotives (with DC traction motors). The heavy haul electric freight locomotive offerings on the market currently (From Bombardier and Alstom) are considerably more powerful than that, were they in the market for replacement power, I would imagine it would be something like the Bombardier IORE locomotives operating in Sweden, which are 7,200 HP six axle units with AC traction motors…
I’m guessing US RRs would love a 6000 hp diesel if it were reliable. An AC44 with full tonnage is making maybe 8 mph; 10-11 mph from an AC60 would be a help. A US main line freight RR that electrified today would want 9000+ rail hp per unit.
(By the way, the E60C on BM&LP etc is 5100 continuous rail hp.)
Interesting discussion. timz’s “9,000 rail HP per unit” [emphasis added for at the rail] - that’s around 10,000 HP / 7,460 kw = 7.5 MW power input. Taking a “unit” to be a C-C with the usual ‘loading gauge’ limits of around 70,000 lb. axle loading/ 420,000 lb. gross weight, at 35 % adhesion = 147,000 lbs. Tractive Effort likewise at the rail, implies a typical speed of about 23 MPH or better in order to fully utilize that HP.
That’s a little higher than is currently typical for some mountain grades - such as the East Slope/ Horse Shoe Curve, where around 16 MPH seems to be the norm - but those are about the only places all that TE and HP could be put to use for a sustained time, so it might lead to slight speed-ups there. Otherwise, the low
[quote user=“Paul_D_North_Jr”]
Interesting discussion. timz’s “9,000 rail HP per unit” [emphasis added for at the rail] - that’s around 10,000 HP / 7,460 kw = 7.5 MW power input. Taking a “unit” to be a C-C with the usual ‘loading gauge’ limits of around 70,000 lb. axle loading/ 420,000 lb. gross weight, at 35 % adhesion = 147,000 lbs. Tractive Effort likewise at the rail, implies a typical speed of about 23 MPH or better in order to fully utilize that HP.
That’s a little higher than is currently typical for some mountain grades - such as the East Slope/ Horse Shoe Curve, where around 16 MPH seems to be the norm - but those are about the only places all that TE and HP could be put to use for a sustained time, so it might lead to slight speed-ups there. Otherwise, the low 20’s is a typical average train speed for most unit and general freight trains (non-intermodal). Perhaps there too the power and TE available from such a unit and needed by the train could be closely matched to the service so as to maximize the usage of all of the unit’s capabilities; or else they could be used in intermodal service where the average speed is in the upper 30 MPH range, which therefore needs much more HP.
- Paul Nor