Who Is Getting SD-90 6000hp

[Mookie]

A question from the curious one. Why would you need more horsepower when the SD70MAC with a unit on the head end and on the rear end, seems to move a lot of coal across Wyoming and Nebraska and on east. Is it because of mountains? I am trying to follow this, but it is a little over my head.

Jen

[Anonymous]

QUOTE: Originally posted by Mookie

A question from the curious one. Why would you need more horsepower when the SD70MAC with a unit on the head end and on the rear end, seems to move a lot of coal across Wyoming and Nebraska and on east. Is it because of mountains? I am trying to follow this, but it is a little over my head.

Jen

Good question. For that situation you do not need more horsepower. I have seen 6000 HP units in bulk service (coal, soda ash, etc,) on the UP but it has been used more in intermodal service where speed is needed. The physics is a little complicated but: HP=speed. Getting over a mountain with a coal train is more forgiving without a tight schedule. Sometimes the railroad will add or remove a unit but overall the DPU operation is great because it keeps a lot of tonnage moving without pulling out the drawbar. As long as the train can keep some speed up the hill it will get to where it needs to.

One point to remember, you can only get 6000 HP with AC, otherwise the wheels would slip or the locomotive would have to be too heavy for the track. Sorry, more physics. The best way to think of it is like traction control on a car, it keeps the wheels from slipping and it provides the most traction. AC allows a lot of pulling power, even if the speed is low.

[Mookie]

Ok - that is clear enough. But freight back here is almost never behind an SD70 - always a Dash 9 or SD38 and SD40's. But then we haven't had a mountain here in just ages. I noticed this weekend, most of the freights were Dash 9's with SD's as helpers.

I appreciate the explanation!

Jen

[Anonymous]

QUOTE: Originally posted by Mookie

Ok - that is clear enough. But freight back here is almost never behind an SD70 - always a Dash 9 or SD38 and SD40's. But then we haven't had a mountain here in just ages. I noticed this weekend, most of the freights were Dash 9's with SD's as helpers.

I appreciate the explanation!

Jen

Jen,
I assume you are referring to BNSF and since they don't have any SD70 DC's it is likely a good example of using DC's for freight, even in DPU, and AC's for coal. I must also assume that the SD's in helper service are MAC's, which they are well suited for. BNSF does a good job of keeping their fleet in the specific services.
Thanks,
Brad

[Mookie]

Good assumption - BNSF Hobson Yard - Lincoln NE. And yes, they do seem to keep everything segregated according to what they are hauling.

Jen

[oltmannd]

QUOTE: Originally posted by crblues

i think that the sd40-2 will always outperform any of these new a.c. traction units any day. yeah, they may gulp a little more fuel, but you need PERFORMANCE in a railroad. the sd40-2 was, and still is the answer.

Wow! Sounds just what they used to say about GP9s when the 40 series was introduced! (you know, 2 GP9s will trump an SD40-2 any day of the week) The GP9 is far simpler in design than an SD40-2 (battery field, not turbo, etc) and on the rare chance you'd lose one of six in the consist, you'd hardly notice it!

Sure, they sip a little more fuel, but reliability is the name of the game, right?

[Anonymous]

But the GE "Evolution series" has a 12-cyl 4400 hp engine. GE never says what kind of engine it is, so I guess it's a smaller version of the HDL (aka Deutz) engine, but they don't say it because ot its bad reputation.

[oltmannd]

This is an interesting thread which raises a few questions.

1. Are the AC locomotives living up to their promise of reduced traction motor maintenance cost? TM maint is about 1/3 of the total cost of maintaining a DC loco. It should be much less for AC. Is it?

2. Is inverter technology still evolving/improving? Are the high power GTOs getting any better? Is the control system improving/evolving as microprocessor technology improves?

And, a comment.

I suspect the 6000 HP AC is dead for the time being, but I suspect we'll see a comeback by the end of the decade. First, EMD and GE have to finish maturing their new diesel engine designs. Sounds like GE is on the way with their new 12 cyl EVO locomotive design and EMD will follow suit. That give you more-or-less proven AC propulsion at the 4500 HP level mated to an engine that still may need some tweaking. Once the engine designs are mature, the next logical step is to go to 6000HP. A 6000 HP AC locomotive will be marketable as a 2 for 3 replacement of C40s and SD60/70s. A pair of them would become an "universal" locomotive consist, able to pull any train, just about anywhere, greatly simplifying the locomotive distribution problem and improving locomotive productivity.

[Anonymous]

QUOTE: Originally posted by oltmannd

This is an interesting thread which raises a few questions.
Is inverter technology still evolving/improving? Are the high power GTOs getting any better? Is the control system improving/evolving as microprocessor technology improves?

Inverter technology has kept evolving, especially in Europe, where almost all new locos (except for EMDs) are AC powered. Current locomotives have better (and faster) microprocessors, water or air cooling (instead of boiling refrigerant cooling), and IGBTs instead og GTOs (lower power losses).

But the point is still this one: will a 6,000 hp locomotive ever be as reliable as two 3,000 hp locos?
When Boeing developed the 777, very reliable turbines had to be developed in order to use just two big (instead of the four smaller turbines from the 747). The odd thing is that one of the available engines for the 777 is made by ... GE!!

[Anonymous]

Ok, so maybe we can't just drop a 16-710 into a SD40-2, however if we remanufactured (different from a rebuild) a SD40-2 with the right cooling systems, oil and fuel equipment, and computers, to the specifications of an SD70, it would be cheaper than a new SD70, or any new loco for that matter. The only drawback would be not being able to place the HT-R (i think thats the name) radial truck under the SD40-2, because the HT-C uses a different connection. Also, what about just dropping a 12-710 into a SD40-2, same horsepower, same electrical output, it wouldn't need much modifications to the existing systems, right?

[SSW9389]

How many miles did GE and GM put on the 6,000 horsepower units before production began? Back in the old days significant demonstrator tours were the order of the day before production of new units began.

[oltmannd]

QUOTE: Originally posted by railpac

Ok, so maybe we can't just drop a 16-710 into a SD40-2, however if we remanufactured (different from a rebuild) a SD40-2 with the right cooling systems, oil and fuel equipment, and computers, to the specifications of an SD70, it would be cheaper than a new SD70, or any new loco for that matter. The only drawback would be not being able to place the HT-R (i think thats the name) radial truck under the SD40-2, because the HT-C uses a different connection. Also, what about just dropping a 12-710 into a SD40-2, same horsepower, same electrical output, it wouldn't need much modifications to the existing systems, right?

Doing the radial trucks would be fairly easy - it's not as bad as replacing Alco tri-mounts with EMD flexicoils - and that's been done (see Conrail 6 axle slugs). The rest would be hard - you'd literally be throwing away just about everything but the cab.

Traction/companion altenator - need new higher capacity
Traction motor blower - need 2 AC motor driven to replace mechanical
Engine - need new
Air compressor - need new motor driven to replace mechanical
Cooling fans - need new multi-speed high capacity
Radiators - need new/split cooling
DB hatch - need new higher capacity
Inertial filters - maybe
Long hood - highly modified to accomodate new equip arrangement
Cab and Short Hood- relocate to keep wt balance
couplers and draft gear - keep
Traction motors - need new
Electrical cabinet - need new
Lube oil cooler - maybe keep
Expansion tank - maybee keep
Main res. - keep
26L air brakes - keep
Control stand - rewire
AC cabinet - replace
Fuel tank - maybe could live with 4000 gals
Trucks - new radial
Frame - might require lenghtening to fit all the components

You can remanufacture an SD40-2 to "like new" for $750,000 or so. If you add in all the new components you'd need, you'd be pushing $1.5M which is what a new SD70 costs!

You COULD remanufacture and SD40-2 into an SD70 but you wouldn't save $50.

Now, dropping a 16-710 and EM2000 control system into an SD50 - that might be a viable rebuild.

[oltmannd]

QUOTE: Originally posted by SSW9389

How many miles did GE and GM put on the 6,000 horsepower units before production began? Back in the old days significant demonstrator tours were the order of the day before production of new units began.

The SD80 demos did a lot of running at Pueblo and later were sold to Conrail. I believe the 6000 HP SD90 demos were built for UP and ran a year or so before the rest were built and delivered.

The history of demos isn't all that great. The SD45 demo'd all over the place but the early production were still dogs. Ditto for the GP40, though this is not a widely know, the early production models were terrible.

[Anonymous]

About those SD80MACs. I see them from time to time here in PA around Altoona, usually for local service or to the engine house in Cresson for maintence. I also see them on branch lines moving unit coal trains. I wonder why NS doesn't utilize those 5000 hp. locos for thier mainline freight or intermodal operations ? ? ? I bet it has something to do with what has been the topic of this subject; reliability. I am sure in the future the SD80 and 90 MACs as well as the AC6000s will be running strong and reliable, but it is a fact that locomotives are not perfect, and from time to time one here and there is going to fail, and taking 6000 hp from a consist is maybe too much, but at this point how hard is it to have a supplemental locomotive(s) on the scene to help out the fallen friend. The SD40-2 is used for everything, and is from my reading on here pretty reliable. I am sure that years from now, there will be little to no more SD40-2s, so sorry for all you loving fans (including myself) of these great machines. RRs will continue to use them, but they will be phased out just like all other old locomotives. A main reason for this I can think of is the old Standard cab, and of coarse the new and more efficient and effective locomotives offered by both EMD and GE. Modern times change, what was then and now a great quality mover, will be no more, and SD40-2s will be a thing of history. Only Time will tell how well the 6000 hp units perform. They obvisouly need improvements and attention. Will they replace the pair of SD40-2s that pu***rains up and down this mountain grade here in PA ? ? ? NS can at least be given credit where it is due-----they don't own one 6000hp unit...... smart move or not ? ? ?