Eastern Railroad Discussion > GE vs. EMD

In a recent post, the usual debate started over which loco builder is better, EMD or GE. The following is from my late website Modern Diesel Locomotives.
(Let me say first that I like EMD better from a railfan standpoint, but I don't have a particular emotional attachment to either one)

GE vs. EMD: Who Makes the Best Locomotive?

Perhaps nothing in the railfan community can trigger an immediate debate, and such strong feelings, as a discussion of who makes the better locomotive-GE or EMD. The answer is not always clear cut, and much depends on what factors are taken into consideration.
Let's start off with a comparison of 2 similar models from GE and EMD: the AC4400CW and SD70MAC
AC4400CW /SD70MAC
Horsepower 4400 /4000
Starting T.E.* 180,000 lbs. /175,500 lbs.
Continuous T.E. 145,000 lbs.(9.9 mph) /137,000 lbs. (9.2 mph)
Standard Weight 412,000 lbs. / 420,000 lbs.
Dynamic Braking 98,000 lbs. / 81,000 lbs.
All weather adhesion 35% / 35%
Length 72 feet, 2 inches /74 feet
*T.E.=Tractive Effort
Minimum Continuous Speed in ( )

From a look at the chart, GE seems to hold a lead over EMD in the basics. The GE AC4400CW has higher tractive effort, horsepower, and dynamic braking ability than a EMD SD70MAC.
Additional Comparisons:
1. The AC4400CW has 1 inverter per axle, while the SD70MAC has only one inverter per truck. This means that an inverter failure on an AC4400 will only cripple one axle, while it will cripple the whole truck of a SD70MAC.
2. Wheel slip control is at the individual axle level on GE AC units, while it is controlled at the truck level on EMD units. Individual axle control in a wheel slip control system is considered superior to control at the truck level only. This is one reason that GE AC units have higher T.E. than EMD AC models.
3. The traction motor cooling systems are quite different on EMD and GE models. EMD units have a mechanical blower system that is driven directly by the engine. This means that the amount of cooling air supplied to the traction motors is dependent on the position of the throttle. Since the max amperage rating is based on 8th notch operation, this reduces the amperage limits of EMD traction motors. GE, on the other hand, uses separate AC motors that supply cooling air to the traction motors regardless of the throttle setting. This is one of the reasons GE units have higher TE and amperage limits than EMD models.
4. EMD units, up until the SD90MAC, have 2 cycle diesel engines. GE uses 4 cycle engines, which are more fuel efficient than 2 cycle models.
5. EMD control systems seem to have an edge on GE, with more advanced capabilities. The rollback mode of the SD90MAC enables it to apply tractive effort and dynamic braking when starting on a hill to compensate for any backward roll and quickly get the locomotive moving in the right direction.
6. EMD's radial truck seems to be superior to GE's and has greatly reduced wheel and
track wear. The radial truck reduces the weight transfer that occurs since the couplers on a loco are attached to the frame. Therefore, the trucks are literally trying to get out form under the loco frame at certain times. This can cause more wheel slip on a GE unit when compared to a EMD model equipped with radial truck. (Although GE is closing the gap on this with their own steerable truck)
7. The new EMD 6000 horsepower 4 cycle H engine for the SD90MAC has more cubic inches than
the GE version on the AC6000CW. This may result in better fuel efficiency and power for the SD90MAC when compared to the AC6000.
8. The current EMD Super Series wheel slip control system, introduced with the SD50 and GP60 series, is generally considered inferior to the GE Sentry wheel slip correction system. The EMD system permits controlled wheel slip, since this can actually increase tractive effort. However, this system wears the contours off the wheels of the locomotive much more quickly than with the GE system. Therefore, the wheels on EMD units equipped with the Super Series system must be turned more frequently to ensure that the wheels wear down evenly. This is especially true if the locomotives are used in lugging service, which is hard on the trucks and wheels.
Is the debate settled? It appears that GE beats EMD in nearly all categories. However, the difference in capabilities between GE and EMD units is not large. Indeed, the difference in T.E. for the AC4400CW and SD70MAC is only about 6%. These models are quite comparable. Each model may be suited for different types of service, however. The greater amperage limits of GE locomotives makes them more suitable for lugging than EMD units. (Contrary to popular belief, AC units do have amperage limits, they are just much higher than DC units. AC units still have a minimum continuous speed limit that they cannot drop below for extended periods before traction motor burn-out. The AC6000CW has a limit of 1790 amps at Max Continuous T.E.) But EMD units may be more suitable for other types of service.
As you can see, this is a complex question, with no easy answers. GE units seem to have a slight edge over EMD models. GE currently holds about 60% of the market, so many railroads have obviously come to the same conclusion. However, GE has much higher production capacity than EMD. The market share between the two builders might be closer to 50-50 if EMD had the same production facilities as GE.
There is also another important factor to consider in the GE vs. EMD debate-maintenance costs. Historically, GE locomotives seem to wear out faster and suffer from higher maintenance costs as age increases, in comparison to EMD units. The very large numbers of older EMD units still in service on Class 1 railroads and shortlines, and the scarcity of older GE "U-Boats" still running, seems to validate this.
Indeed, the Dash 7 line may be nearing the end of the line as UP and CSX are retiring them as major failures occur. In the meantime, the EMD SD40-2, GP38-2, and GP40-2 appear to have many years of service left in them. However, it is also quite possible that many old GE's will be rebuilt and still see service for many years.
In general, it may be said that older EMDs are superior to older GEs, but newer GE models (from the Dash 8 and up) are a little ahead of newer EMDs in most categories. It is also still too early to tell whether or not the current GE offerings will wear out faster than the newer EMDs, as happened with the U-Boat and Dash 7 line. Only time will tell.

More from another page from my old site:

There seems to be a curious anti-GE feeling from a majority of the railfan community. In the following article, I will address this issue. My opinion will probably go against the average railfan's feelings. I will just go ahead and say it: I think GE units are slightly better than EMD's. Please don't flame me!
Let's address the main arguments pro-EMD fans use to explain the 60-70% market dominance of GE:
1. GE has a much higher production capacity. They can produce locomotives much faster than EMD and in much larger numbers. This might explain a small part of GE's market share, but not all of it. If GE units were poor performers, than the RR's would not buy them, even if GE could make them much cheaper and faster than EMD.
2. GE will finance anyone. Once again, this applies only in a very small number of cases. The primary customers of GE are huge companies with considerable financial resources. I doubt they need much help in this area. Operating leases and equipment trusts are available from EMD as well, probably on very similar financial terms.
3. GE has better customer service. Well,if this is true, GE deserves their market share. Customer service is very important, especially in the cutting-edge technologies in new AC units.
The hard core fact is that GE has a large market share because they put out a slightly better locomotive than EMD. GE has been number one for a long time now, and operating costs and maintenance records are available to compare GE and EMD locomotives. And yet, GE remains in the lead! This tells us something. For example, NS will have over 700 C40-9W's by 2001 that they have purchased since 1996. NS is well known as a conservative company that steers clear of risky new technologies until someone else has worked the bugs out. Indeed, NS has not purchased a single AC unit, even after receiving 17 SD80MAC's in the Conrail break-up. The company purchased 90 SD70 series units, the EMD version of the GE Dash 9, but instead returned to GE for several new orders of C40-9W's. Would frugal NS purchase locomotives than cost more to operate just because they can be built more quickly? I don't think so.
Sales figures tell the story. Let's compare:
Overall Sales of GE and EMD
(Including exports)
1993 1994 1995 1996 1997 1998 1999 2000
GE 447 646 720 601 720 815 ? ?
EMD 150 274 427 304 324 482

These kinds of sales do not result simply because of production capacity. The railroads obviously like GE's better than EMD's. A simple look at the specifications of GE and EMD locomotives shows that GE's lead in nearly all categories. The performance difference is only about 3-4%, but that is a difference many roads consider important.
History is a good guide on this subject. In 1946, Alco held about 40% of the new diesel loco market, and was within striking distance of EMD. However, Alco's market share quickly eroded and Baldwin and Fairbanks Morse never even came close to that figure. Only a few years afterwards, EMD had increased its market share to 70-90% at times. Why? The answer is simple. A few years of operating experience had provided strong evidence that EMD locomotives were more reliable and, overall, cheaper to operate than the competition. This enabled EMD to maintain market dominance for over 40 years.
Although we do not have access to operating records, the situation today must be similar today, but with GE in the lead. The simple truth is that the railroads would not have bought thousands of GE Dash 8, 9, and AC4400CW's the last 10 years if they were not highly reliable and cost-effective to operate. EMD sales pale by comparison of model-to-model.

One other argument made by pro-EMD fans is that GE units wear out much faster than EMD units. This does seem to be true, at least for the Dash 7 and U-boat line. (We do not yet know how long the Dash 8 and 9 series units will last.) The GE Dash 7 series is an endangered species on Class 1 railroads, while EMD Dash 2 units still make up a large portion of railroad rosters and will continue to do so for many years. But could this be because GE's were worked harder? GE's took the place of many Alco's in heavy lugging service that may have worn them out faster. In addition, GE's were minority units on many roads for many years, meaning that may not have received proper care and overhauls as EMD's did. We all know how minority Alco's, Baldwin, and FM units were frequently retired early to cut down on spare parts inventories. (This defense, I realize, is quite debatable)
You can find more on this subject on my GE vs. EMD page here.
My personal view: I would not describe myself as pro-EMD or GE, I like both companies equally and I wish EMD had a greater market share for the sake of variety out on the tracks. My favorite modern locomotive is the SD70MAC, not a GE. I also am quite fond of the SD9043MAC and the phase I SD90MAC-H. Surprised? In the GE vs. EMD debate, I feel the facts speak for themselves. Does EMD put out a good locomotive? Yes, a very good one. But GE also builds very good units. The anti-GE feeling among many railfans seems based mainly on nostalgia. We are all individuals and are entitled to like what we want, but the evidence indicates that GEs are not junk, like many fans say. Each builder puts out a unique product, with a charm all its own.

The debate continues..........

Brent

good factual arguments, far too scarce recently...but why do you say:

"....We all know how minority Alco's, Baldwin, and FM units were frequently retired early to cut down on spare parts inventories. (This defense, I realize, is quite debatable)"

what's so debateable about it? It's a cold, hard fact. Maintaining inventories is a huge expense for the RR and the mfgrs.

also the extreme abundance of the -2 EMDs means that cannibalization is much more viable to stretch their life. Since not nearly as many -7s were sold, boneyard pickings are more difficult. Doesn't mean one is better than the other, just that it's more practical to keep around.

I look at longevity. How many B23-7's and B36-7's are around and still pulling worth a darn as compared to how many GP38's, GP40-2's, and SD40-2's are around? Since thats unfair due to builder totals, take a look at how high the percentage is of remaining EMD's built as compared to GE's of those competing models.

It is my firm belief that EMD of GM builds a far superior product that will last more than ten to fifteen years, unlike the GE's. I also think that the railroads who invested in numerous SD70's are going to be very fortunate to have them around when their dash eight and nine fleets start to die around 2010 or 2015.

The only reason any new GE might be better is because of the fifth word in this sentence; they're NEW. Until a GE lasts 30 to 40 years and still pulls solid like the GP38's, SD40-2's, or SD70's will, I'll never give them credit for building a good locomotive.

Even the trade-in deal seems raw. Companies justify buying GE because they are cheap now and will trade in for new units in about ten to fifteen years when they start dying. So, if you start out with 1000 dash nine's, you might get 500 to 600 new dash whatevers. It seems more practical to buy 1000 SD70's that will last 35 to 40 years, does it not?

May EMD rule the world... :)


Scott H

What about a comparison on price? Are GE's original selling price that much lower than EMD's?

I would assume that if they are building more units that can absorb their overhead better and therefore have a lower unit cost. In a competitive situation this would provide an avenue to offer a lower selling price.

(Yes, I know that locomotives are not really built mass production style but overhead is overhead.)

This debate will rage on until one of the builders drops dead, and even then, like Baldwin, Alco, and Fairbanks Morse, there will be those who lament the loss and proclaim that they actually built superior locomotives: They just didn't get a chance because they were either misunderstood, or because of some perceived emotional bias on the part of the railroads.

I'd like to make a few comments on the points made, not that they will clear up anything, just a different perspective on what they mean.

> 1. The AC4400CW has 1 inverter per axle, while the SD70MAC has
> only one inverter per truck. This means that an inverter
> failure on an AC4400 will only cripple one axle, while it will
> cripple the whole truck of a SD70MAC.

An important side effect of this is that with one traction motor cut out, the GEs still produce full horsepower. That means that they can continue their trip without time loss, assuming there isn't a ruling grade that required the tractive effort provided by the missing axle between the point of failure and the train's destination. Further, cutting out one axle on a GE isn't considered a safety defect by the FRA, so the locomotive doesn't have to be immediately routed to a shop for repairs. Advantage GE

With the EMD arrangement, a failed motor will result in the loss of almost half the horsepower produced by the locomotive (it derates) so there is an impact on the train's running time. Advantage GE.

> 2. Wheel slip control is at the individual axle level on GE AC
> units, while it is controlled at the truck level on EMD units.
> Individual axle control in a wheel slip control system is
> considered superior to control at the truck level only.

There has been great debate about the value of one over the other since the first locomotives were produced. The proof is in the adhesion rating, which you note as 35% for both locomotives. That implies that they are equally effective in putting horsepower to the rails. Draw.

> This is one reason that GE AC units have higher T.E. than EMD
> AC models.

Not exactly. The tractive efforts listed (starting and continuous) are strictly electrical ratings for the motors. The GEs simply have more robust motors than the EMD locomotives. Slight advantage GE.

> 3. The traction motor cooling systems are quite different on
> EMD and GE models. EMD units have a mechanical blower system
> that is driven directly by the engine. This means that the
> amount of cooling air supplied to the traction motors is
> dependent on the position of the throttle. Since the max
> amperage rating is based on 8th notch operation, this reduces
> the amperage limits of EMD traction motors. GE, on the other
> hand, uses separate AC motors that supply cooling air to the
> traction motors regardless of the throttle setting. This is one
> of the reasons GE units have higher TE and amperage limits than
> EMD models.

Interesting line of reasoning, but I'm not sure it is that critical. The continuous ratings of the motors certainly require a given amount of motor cooling air. Most of the time, the locomotives will be operating in notch 8 whenever the rating is critical to getting a train over the road. EMD will have designed the blowers to provide the required amount of air for that operation, so the fact that the blowers are mechanically driven rather than electrically driven is immaterial. GE selected electrically driven blowers mostly to improve fuel economy, and to permit rapid replacement whenever there is a failure. The tradeoff was a higher initial cost of the locomotive. Draw.

> 4. EMD units, up until the SD90MAC, have 2 cycle diesel
> engines. GE uses 4 cycle engines, which are more fuel efficient
> than 2 cycle models.

This has aways been the theoretical argument, but in reality, EMD and GE have been neck and neck for fuel efficiency since the Dash 8 line was introduced. Draw.

> 5. EMD control systems seem to have an edge on GE, with more
> advanced capabilities. The rollback mode of the SD90MAC enables
> it to apply tractive effort and dynamic braking when starting
> on a hill to compensate for any backward roll and quickly get
> the locomotive moving in the right direction.

This feature is perhaps a nice to have, but whether it is there or not won't particularly affect the railway's bottom line. Further, I think GE has developed a similar system. Draw.

Another comparison can be made of the troubleshooting capabilities of the microprocessor system. Now this does put money to the bottom line by making maintenance easier, and keeping locomotives out on the road instead of in the shop. Most shop foremen I know prefer the GE micro for electrical troubleshooting. Advantage GE.

> 6. EMD's radial truck seems to be superior to GE's and has
> greatly reduced wheel and track wear.

I think the jury's still out on that conclusion. GE has redesigned their radial truck to address some maintenance problems, and the new version should perform as well as the EMD R truck. They are, after all, designed to do the same thing.

> The radial truck reduces the weight transfer that
> occurs since the couplers on a loco are attached to the frame.
> Therefore, the trucks are literally trying to get out form
> under the loco frame at certain times. This can cause more
> wheel slip on a GE unit when compared to a EMD model equipped
> with radial truck. (Although GE is closing the gap on this with
> their own steerable truck)

It's not because the trucks are radial that results in reduced weight trainsfer, as both standard trucks and radial trucks can have low weight transfer designs. EMD introduced a low weight transfer truck with the dash 2 line (the HTC) and GE came along later with the trucks under the Dash 9 locomotives. MLW actually lead the way with their Dofasco truck 'way back in the 1960s, followed by the Alco Trimount. Thus, other than the fact that GE was behind EMD in timing, draw.

> 7. The new EMD 6000 horsepower 4 cycle H engine for the SD90MAC
> has more cubic inches than the GE version on the AC6000CW. This
> may result in better fuel efficiency and power for the SD90MAC
> when compared to the AC6000.

Purely speculation. Much depends on cylinder head design, scavenging, and auxiliary losses. It's too soon to tell, since both builders are still refining their designs. Given the past ability of both builders to match the other in fuel efficiency, I would call it a draw.

> 8. The current EMD Super Series wheel slip control system,
> introduced with the SD50 and GP60 series, is generally
> considered inferior to the GE Sentry wheel slip correction
> system. The EMD system permits controlled wheel slip, since
> this can actually increase tractive effort. However, this
> system wears the contours off the wheels of the locomotive much
> more quickly than with the GE system. Therefore, the wheels on
> EMD units equipped with the Super Series system must be turned
> more frequently to ensure that the wheels wear down evenly.
> This is especially true if the locomotives are used in lugging
> service, which is hard on the trucks and wheels.

GE's Micro Sentry system, which was introduced during production of the Dash 8 line, is also designed around the concept of controlled creep, so there is no difference in the intent of the two systems. It is the standard system used on all new locomotives, and has been offered as retrofit on older locomotives.

When comparing manufacturers, one system works better under some adhesion conditions, and the other system works better under other conditions. The ultimate measure of the effectiveness of the systems is the adhesion rating. Again, as noted in the beginning comparisons, both are rated at 35%, so it is a draw.

> Is the debate settled? ...

Not likely.

> As you can see, this is a complex question, with no easy
> answers. GE units seem to have a slight edge over EMD models.

Agreed.

> Historically, GE locomotives seem to wear out faster and suffer
> from higher maintenance costs as age increases, in comparison to
> EMD units.

Be careful of making too many conclusions based on this, and you do acknowledge the issue in the rest of your comments. GE went through a metamorphosis with the introduction of the Dash 8. They recognized that if they were to stay in the business, they had to make a locomotive that was reliable and durable. The dash 7s and earlier were not, and even some of the early Dash 8s were not as good as the latest offerings, hence the preference for EMD locomotives of that vintage.

EMD, however, proceeded to demonstrate they were capable of screwing things up with the introduction of the SD-50, shattering everyone's illusions of their infallibility. They weren't a bad locomotive, just not the shining star that railroads had come to expect from the builder that produced the SD-40-2. The 50 series sure helped boost GE sales of the new Dash 8 line. I would say the builders are now on a par, but EMD might have a slight edge in how their locomotives are assembled. Their 710 engine seems to have problems, though, in the SD-75s. We'll have to see how the H engine of both builders settles in, both need more work, though EMD is certainly behind. Overall, GE is better in some areas, EMD in others. Draw.

> 2. GE will finance anyone. Once again, this applies only in a
> very small number of cases. The primary customers of GE are
> huge companies with considerable financial resources. I doubt
> they need much help in this area. Operating leases and
> equipment trusts are available from EMD as well, probably on
> very similar financial terms.

Equipment trusts can only come from banks. The builders don't offer them. Pretty well all leases are also held by financial institutions, and the railroads pretty well all arrange them by themself without the builders. Where the builders will differentiate themselves is in the intial price of the locomotive, and what's included in the package. It becomes a game of who blinks first with the sales package.

> 3. GE has better customer service. Well, if this is true, GE
> deserves their market share. Customer service is very
> important, especially in the cutting-edge technologies in new
> AC units.

There is no question that GE has better after sales support than EMD. Advantage GE, but it doesn't say anything about how good their locomotives are, which was the initial question.

> The debate continues..........

Yes.

It is a lot easier to Identify EMD over GE's. It always has and always will.

Cv

>>>>>>>>>>>>>>>>>One other argument made by pro-EMD fans is that GE units wear out much faster than EMD units. This does seem to be true, at least for the Dash 7 and U-boat line. (We do not yet know how long the Dash 8 and 9 series units will last.) The GE Dash 7 series is an endangered species on Class 1 railroads, while EMD Dash 2 units still make up a large portion of railroad rosters and will continue to do so for many years. But could this be because GE's were worked harder? GE's took the place of many Alco's in heavy lugging service that may have worn them out faster.<<<<<<<<<<<<<<<<

GE's worked harder?? Now I've never been in the engineer's seat, but from years of watching the L&N and CSX haul coal out of Eastern Kentucky I just can't agree with this statement. EMD's slugged it out just as hard and as often on the likes of Elkatawa, Crooked and Richmond Hills as well as Duff Mountain and Hagan's Switchback as the GE's did. After the formation of CSX, the EMD's were almost always the power of choice for helper/pusher engines as I have dozens of SD40/SD40-2 roster shots taken at these helper stations over the years. GE power sitting at Richmond or Livingston was considered a banner catch on my weekend trips home from UK. Why was this? The same seemed to have been true for the run down the Clinchfield between Shelby and Dante. Having found the cash to frequent that area only after 1985, it seemed EMD was always the builder to be placed on the rear of an extra south making a run through the Breaks until the introduction of AC power.

The EK coalfields have always been where old engines were sent to die mainly because coal was never really a high priority movement and if power died enroute so be it. The U30C's pulled their hearts out right up until major failures and the 90-odd C30-7's were falling fast in their footsteps until the invasion of Dash 8's, 9's and AC units reduced the need for 3 engines up on the point. Lets see, when were the U30C's built? 1967 or so. When were they finally retired off CSX? All gone by 1993-94 maybe? 25 years of service. The C30-7's arrived about 1979 if memory serves and are almost all gone as we speak. Only 22 years of service. The first L&N SD40-2's arrived in Corbin during March '74 and are still to be found grinding up the Kentucky grades at a snails pace or pulling hump duty. One of those 1974 era units was assigned to helper duty at Blackey, Ky under cover as CSX 8165 earlier in the year. 27 years, thousands of coal trains and still pulling (or pushing in this case) hard...........

How are the newer units expected to hold up? Good question but my buds at Corbin, Russell and Huntington sure see a lot of these new GE units passing through the shops these days. Fact: Huntington currently has a nice big banner inside the shop reading "Target SD40-2's for zero failures". I bet they would never dare hang a "Target AC60's for zero failures". Anyone like to put some money down????????

Robby

<<<GE's Micro Sentry system, which was introduced during production of the Dash 8 line, is also designed around the concept of controlled creep, so there is no difference in the intent of the two systems. It is the standard system used on all new locomotives, and has been offered as retrofit on older locomotives. >>>

I believe that the GE system does not allow wheel creep. This is according to the excellent book How Diesel Electric Locomotives Work.

Thanks for the intelligent debate! (Some of you) It's nice to hear arguments other than simple emotional ones.

pafan wrote:
>
> I believe that the GE system does not allow wheel creep. This
> is according to the excellent book How Diesel Electric
> Locomotives Work.

The book is wrong on that point. They probably based it on information from early Dash 8 designs, which did not allow creep. GE developed a creep control system in about 1988 or 1989, and it has been applied to all their microprocessor locomotives since. There is a retrofit kit for older Dash 8s, and one now available for some types of Dash 7 locomotives.

Yes the old debate continues for the last 30 years.

My question to those mechanically qualified out there should EMD have stuck to improving what they know the best, that is the 2-stroke diesel engine?

Also is 6000hp the engineering limit to a 16 cylinder engine that can fit inside a locomotive?

Is there a real need to go beyond 4000-4400hp????

As a railfan I love anything 2 stroke, but if I was the Chief Mechanical Engineer for a railroad I probably be thinking of the shareholders money.

I think that in recent years from what I have read there seems to be a malaise in EMD sales and after sales service. This may be what truly divides the two teams, not their locomotives' performance.

To give it another football analogy, the difference may lay with the coach and not the players.

I think that the SD70MAC's finest hour will come when in another 10 years time we realise that they were the SD40-2s of the 90s.

Remember in the 70s when the horsepower race was on and then it fell back to the 3000hp level.

Maybe we are in a cycle of GE dominance followed by a period of EMD dominance.


Regards,

Grahame
AUSTRALIA

I was down at L'Enfant DC last Saturday and noticed the following: CSX is using SD50's and SD60's on its mixed-freight trains and using Dash 8's on its intermodals. Is this just coincidence or is there a reason for that?

Rumor has it that EMD is developing a 10,000 HP diesel. I don't know how true that is. I doubt that the horsepower race will end at 6,000.

> My question to those mechanically qualified out there should
> EMD have stuck to improving what they know the best, that is
> the 2-stroke diesel engine?

There is a feeling among some people that the 2 stroke engine will not be able to meet the tightening environmental regulations as easily as a 4 stroke. This may be why EMD has moved toward a 4 stroke as their new design.

The problem with the 2 stroke is twofold: They tend to burn more lubricating oil as they run, which add to pollutants, and there is a carry-over of some of the charge when the cylinder is scavenged, meaning that some unburned fuel can pass through the cylinder from intake to exhaust, and increase hydrocarbon emissions. These are both difficult problems to solve and sustain fuel efficiency at the same time.

> Also is 6000hp the engineering limit to a 16 cylinder engine
> that can fit inside a locomotive?

I doubt it. Both builders likely have plans for increasing the horsepower, if they see a marketing need for it. Look at the old GE engine, as an example. It started out at about 2500 HP, and with modifications is now producing 4400 HP. One problem is to find a place to put all the fuel that a larger engine would consume. The underframe is pretty well full now.

> Is there a real need to go beyond 4000-4400hp????

It depends on the price of the locomotive. Intermodal trains tend to require lots of horsepower, and if a higher horsepower locomotive can be produced at lower cost per horsepower than present locomotives, it will sell. UP, for example, puts 15000 to 20000 HP on the front of some of their intermodal trains.

Here is my opinion:
GE SUCKS
EMD RULES

Here is why:
Long lived EMD's get ran into the ground (mechanically) by GRS and they still give all they have, but the remaining GE's have all failed, all 3 are awaiting Disposition, this includes 288, whitch was in TRAINS magazine a few months back.

Us technical and railfan types tend to evaluate things on performance or technical merits but, in the final analysis, the only real measure of success is sales, or maybe long-time economics, since they are closely related.

The world is full of performance-inferior products that were great commercial successes. And, on the other hand, there are plenty of technically superior products that have totally flopped in sales.
(I'll probably be beaten up badly for saying this but in the RR field the FM Trainmaster was in many ways a superior product in its time but a commercial failure).

So, this kind of discussion is fun and informative, but, when the day is done, sales rule. I guess that makes the SD40-2's a great winner!

Actually, I think there are some people who would agree with you. The FM H-24-66 "Trainmaster" was supposed to be a great locomotive that simply did not sell well. I forget where I read it, but I'll always remember the phrase describing that the "Trainmaster" as being "born too big too soon."