hi yall from the hurricane south!!
question please,as we all know the problems ge an emd had with the big boys sd90 n ac6000, both being 6000 hp, 10 years er so later are any up to snuff,er problems corrected? i heard csx has their ge up to 6000 hp, why not up? has emd corrected the problem in their 6000 hp boys? why such a big jump from 4000 hp to 6000, what about 5000 hp? isnt it in their vocabulary? common sense says says a 6000 hp unit will replace 2 , 3000 hp, or 2, 5000 units replace 3, 3000hp units, ect,ect.
whats on the drawing boards now? rrs need more power as last week piggy back and containers set a new worlds record 250,000 units in a week!!!
have they made aluminum trailer and container holding bays like they have for coal cars? the goverment needs to get more research done in how to get more from less. as we know as gas prices go up so do rr shipments. sorry to get off track but, im not all on track!! thanx!! god bless!!
actually, they did have 5000 hp… the SD80Mac… Conrail was the only railroad to actually purchase them
I seem to remember reading a discussion about this in another thread, and that there’s a point where a six-axle loco could have too much power. An SD90 or an AC6000 is beyond that point.
The UP has some true AC6000s, running on all 6000 hp. They’re all numbered from 7500 to 7579.
When the SD90 and AC6000CW came out they were in effect the test beds to for the brand new engine blocks for their respective companies. Hence the bigg teething problems.
I think the RR’s have settled on the 4400 HP 12 cylinder versions of the new EPA Tier 2 engine blocks because they dont want put too much HP in one unit. Not because of traction problem w/6000 HP unit but operational concerns of putting too much eggs in one basket. Example if a train has two 6000 HP unit on a given train and you lose one unit you are down 1/2 power and have 6000 HP left and on the same train you have three 4400 HP units for the same train and you lose one then you are down only 1/3 power and have 8800 HP left to continue your trip.
Any thoughts or comments?
I watch the “Big Power” tape put out my TRAINS, and (if I remember right) that a 6000 HP loco doesn’t really have that much of an advantage cause the traction motors cant deliver that much power to the rail…(thats what I can remember…I might have to watch it again…) But anyway…it was an awesome video…
A 6000 HP AC locomotive = 1-1/2 4000 HP DC locomotives in every respect.
IF
The builders can improve the reliability of the diesel engine
AND
IF
the RRs can figure out how to deploy the locomotives and get anywhere near a real 2:3 replacement ratio (this will likely require RRs to have better locomotive distribution planning tools available)
THEN
You see lots and lots of 6000 HP AC units.
From Al Krugs website: http://www.alkrug.vcn.com/home.html
Those Superpower units.
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.
The railroad I work for uses 12,000 Hp on their coal trains through here and we go up the hills at about 12-13 mph. Note that you can replace the 12,000 Hp of 3 SD70MACs, or the 12,000 Hp of 4 SD40-2s, with the 12,000 Hp of just two SD90
He’s making the point that the extra 2000 HP per unit is wasted in heavy haul service - where TE rules (not HP). The only point I’d quibble with is that if you’re getting 30% adhesion on andSD40 you’re pretty deep into the traction motor’s short time rating. You COULD do 2:1 replacement with 6000 HP ACs as a rule.
Elsewhere on the RR, where HP rules, you’d be replacing DC machines with these high HP AC- and that’s an entirely different story!
Also, the “all weather” (rain sleet snow, etc) adhesion rating for locomtive is something like this:
AC = 35%
DC high adhesion = 25-27%
DC Dash 2, Dash 7 = 18-21%
My experience with AC units in heavy coal service is get the train started and get out to number 8. The wheel slip system is so good on AC units that you will not get the knuckle busting lunge if the engine won’t hold the rail, instead the engine will apply all the tractive effort it can transmit to the rail that the available adhesion will allow. You can’t do that with a DC unit. The DC wheelslip system will allow the lunge and tear your train up. I’ve taken a 16,000 ton coal train up a 1.2% grade in the rain at .25 (1/4) mph with 2 GE AC4400’s. I would have hung up with DC units as I would have had to reduce power to keep from getting the lunge. Even with AC’s when you’re down scratching there’s some serious pucker factor, but you have to have faith. If you’ve got the faith it’s amazing what they’ll do.
Soo 6049
EMD’s website is now listing a JT56C, an export 6000 HP unit for China.
It will be interesting to see how these go, but Chinese axle loads are genearally lower than in the USA, so thse units might be for high speed traffic.
M636C