Future of 6000HP Engines

[Anonymous]

Does anyone have any feedback on the future of the 6000HP engines that GE and EMD produced? Has anyone ordered these lately? From all that I have read and feedback in the forum discussions these monster AC units have reliability problems and are hard on the rails. Also, who owns the most, UP or BNSF?
Larry

[Anonymous]

I don't think BNSF has any 6000HP units but I know that CSX does

[Anonymous]

How did I forgot about CSX and NS? Thanks.
Larry

[Anonymous]

I think that it's only CSX and UP that Has 6000HP units

[Anonymous]

UP has the largest fleet of 6,000hp units, both SD90MAC-H and AC6000CW units.
CSX has a small fleet of AC6000CW's
CP has a handful of SD90MAC-H units.

Nobody else has 6,000 hp units.


Insofar as the reasons that these monsters have not become the standard in North American freight practice, the problems are manifold:including engine reliability and heavy wear and damage to the rails. These units were built for high speed freight service (in drag service such as coal trains, the slow speeds don't allow them to develop their maximum hp,meaning that they perform no better than lower horsepower units), in practice the railroads are finding that the a 3 unit set of 4,000-4,400 HP units offers better reliability and performance than two 6,000HP brutes, not to mention that AC propulsion is considered too costly for this type of service(unlike in heavy haul/drag service).
It's too bad, one of the coolest railroad sights I've seen are pairs of AC6000CW's running on CSX's Boston line...................

[Anonymous]

D'ho forgot CP.

[edblysard]

Keep in mind that at some point techonology oreruns the demand for a product. The concept of Mulit-unit was what helped put steam on the back burner, and made the GPs and SDs the locomotives of choice. With a 6000 hp unit, more that two would be sorta overkill, so why pay for these things when 3 or 4 of your SD70s would do the job? Look at UPs Gas Turbines. Wonderful techonology, something like 8000hp, and they only saw service in a limited area, for about ten years. What the railroads have discovered is they really dont have a daily use for a 6000hp AC unit. It would be like your pizza delivery guy using a Kenworth for a delivery van. You could, but why would you want to?
Ed

[Anonymous]

Ed, I will agree with you on the Horse-Power. But I believe the future is in AC propulsion. AC drive is so much more efficent. Right now it may not seem so, but in the future AC will be cheaper to maintain also.
TIM A

[edblysard]

For the big motors, maby. But when you need the motor to load right now, dc traction motors work best. I would want a fleet of motors that were multi use, so far AC dosnt fit the bill. Your aware that all motors use a alternator for electric power, then invert it to dc for the traction motors, or left Ac but regulated. The diffrence is in the traction motors. For quick hard starts, AC dosnt hold up. I dont think you will see wholesale AC traction motors untill they can make them reliable, cheap to produce, and cheap to maintain.
Stay Frosty,
Ed

[Anonymous]

There are several technological issues to resolve, but I think the future is in AC. I predict in 10 years AC units will dominate. If I'm wrong, you can slap me later.

[Jackflash]

Ed, the electrical path between the alternator
and traction motors on modern locomotives is as
this,,,,for AC motors the alternator generates
alternating current it is then rectified to DC
current then it is inverted back to AC current
for the moters.
for DC motors the alternator generates AC current
it is then rectified to DC for the motors (the-
inverting stage is left out) this is over-simplified of course, I like the DC motors too
but I think sometimes in the future AC motors
will be the thing, if for nothing more than the
maintance issue, no stall burns, no flash overs
ect, ect, also I'm not at all impressed with
the 6000 HP units (horsepower = speed, and at
a slow speed you can tell you dont have 3 or 4
engines pulling ) thanks jackflash

[edblysard]

So it would use a thryster, (sp) or a diode trio curcit like a automobile alternator, DC one side, Ac the other, use whichever you wish, just run it through a inverter to make it ac again.
I get the no stall thing, most induction motors can be stalled without damage. But until the ACs can pull as hard and as quick as DCs, then there will still be some guy who dislike them. But yeah, when they become more common than at present, the carriers will not have much choice but to go AC on most road power. But us switching roads will end up being the last home of the old DC motors, you just cant beat em for kicking cars...
Stay Frosty,
Ed

[SSW9389]

Besides the aforementioned roads of CP, CSX, and UP there are two other owners of 6,000 HP locomotives. GE has retained several as leasers and demonstrators and there are eight on a railroad in Austrailia called BHP. BHP is having very poor results with its AC6000s.

[Justicar]

I can offer only anecdotal evidence....

Last trip we had the CP 9301 from St. Paul to Glenwood (and points west) on 493-22. Had 1-90-3000'ish and 5000'ish. My second time on one of our 6000's. Seemed like it pulled our BN hill (0.6%, IIRC) pretty well...better than our Mac90's and regular GE's at the track speed of 25.
I'd say it pulled pretty much right at track speed the whole way which is better than the normal assignment of a GE 4400, but didn't seem to pull proportionally better. My hoghead seemed pretty pleased with it but as we talked at the beginning of the trip it broke down enroute. Funny. Fortunately, it was right at the end and wasn't a critical failure. We got an alarm on the #2 traction motor blower and reset it twice but after that it was continuously complaining with the characteristic "electronic" bell of our MAC's...wished I had brought my duct tape. We called the Diesel Doc in Calgary and he suggested cutting the traction motor out. Since it was the end of our day we didn't bother with doing anything to it and just merely reported.

I also noted it rode rougher than most of our other MAC's and GE's.

Lastly, CP's 6000 hp MAC90's are 9300-9303 and I'm not sure if they're all still in service.

[Anonymous]

Currently their future is dead, the roads that have 'em (UP,CSX,CP) will undoubtedly continue using them for a while, as they are nearly brand new, but they found they really didn't work out like they hoped. They were hoping to do a 2 for 4 swap (4 3000hp units gotten rid of for 2 of these), but they found it limited flexibility for one thing, and the reliability of these units, especially when they were new, just wasn't up to snuff. You could loose a single 3000hp unit out of a 4 unit set and usually still make it, albeit slower, but you loose one 6000hp unit out of a 2 unit set, your in deep s....! I believe most, but not all of the reliability issues have been solved as we get 90macs on stack quite regular now. Very seldom get the ac60's though, except on grain trains. Also, the 90macs had some ride issues, which have since been resolved (they were very, very bouncey). I had never heard anything about these units being hard on the rail. They are only slightly heavier than a normal unit, and especially the 90macs with their radial trucks, I would be quite surprised to find they did any damage to the track.
One thing I do have to say about both the GE and EMD models, they have awesome dynamic brakes, especially as you get down to to 20-30mph. there's nothing else out there like 'em. Also, at least on a fairly light stack train, once they finally get up to putting out their rated horsepower, they accelerate very well, it just takes 'em too long to load up in undulating territory (more of a problem w/GE than EMD)

[Anonymous]

Please elaborate on the problems and benefits of ac vs dc traction motors. What is a stall burn and a flash-over, ect.... I often hear the terms but am not shure what is ment by them. The comment about 2 6000hp units vs 3-4 3000-4400 units interests me. Is the difference in the traction? After all; how much power can be effectively transfered by a given number of wheels? Thanks, Ron

[Anonymous]

I'm just wondering, did the railroads request the units or did the makers dictate the 6000hp units? I read back in 97 that it was the UP who actually requested the units and the others jumped on board the idea.

[PaulDannenberg]

From Paul D , Australia
I,m not sure if the term " very poor results " is 100% right on BHP's AC6000 units. These units have been put in an environment that tests new ideas and equipment to it's limits. BHP AC's weigh 223.5 U.S tons , and have a T.E of 890kn (sorry I dont know what that translates into pounds). They have G.M style cab windows and are about 2.5 inches lower than U.S. models.
As for their use I am not exagerating the tonnages hung behind these locos ---- massive.
Consists have been changing but an example would be 3 x ac6000's hauling 240 ore wagons with a total loaded weight of 165 U.S. tons each , thats a 39 600 ton train. These trains run day in day out , no weekends , no holidays as soon as they are fueled and preped for a run they go back out. Just to make it interesting the environment in the Pilbara is something like Mars. Honestly summer is 6 months a year and 48 degrees centigrade all day ( 117 degrees f ) , winter cools down into the 90 degree f range. Why these locos have snow plows I have no idea. Environmental conditions are harsh , all mid train units have metal shields over the windows because they get sand blasted with sand and ore dust quickly ruining the glass.
An interesting perspective would be BHP's G.E. Dash 8 locos that make up the bulk of the fleet. Most of them have chassis and Hi-Ad bogies from their Alco M636's , the entire loco above the chassis being G.E.
4 of these locos handled 220 car trains for many years. Consists are now varying and mixing new and old locos but 300 car trains are running regularly.
So if an AC6000 is seen to be not performing , the task it has been assigned must be considered.
If anyone would be interested in hearing about 3000 hp G.M A.C's we run on this side of the country let me know.