6000 HP LOcomotives

Trains Magazine General Discussion
1

I don’t know if this topic has been discussed before, but I’ll bring it up anyway.

What is the story with 6000 HP locomotives? It seems like all the new orders are for locos in the 4300 HP range, whether they use AC or DC traction motors. I read stories that both GE and EMD had problems with their new 6000 HP prime movers, and that many of them were in the shop for repairs/upgrades.

What is the real story? Did the builders overestimate the desire of the railroads for these higher horsepower locomotives, or is the problem that they are just not ready for prime time?

Mike Chern

2

Mike,
I brought this subject up four or five months ago and got some good feedback on it. Just getting use to this new format myself. I think there is a way to go back and look at old forum issues, just haven’t figured it out yet. Maybe someone out their can help in figuring out how to find old issues in this new forum. The bottom line is that the 4300/4400 HP engines now are the preferred HP engines and seem to hold up better in all conditions versus the 6000 HP.

Larry

3

4500HP is the new engine, the AC45 that GE’s debuting on UP, and the so called SD89MAC, a 4500HP version of the 90 MAC-H.

4

I believe another factor in the unpopularity of the 6000hp units were issues the UP faced with their Centenial (6900’s) locomotives, the one with two engines per locomotive. The problem was that with so much power in one unit,assigning power to a train was difficult because of reliability issues. If you have two SD40-2 locomotives, and one goes down, you can usually keep the train moving with 1/2 the power. If you have one 6000 hp unit and have a problem, you’re SOL. Plus the large price difference did not justify the extra 1700hp. In addition, servicing one unit takes that much more power out of service.

There are surely more issues, but these are all I remember.

5

The 6000HP EMD’s and GE’s are shop queens. they spend more time there than on the road. That’s why the UP bought 1000 SD70’s [8D] [:D]

I’m sorry but the EMD H engine is junk

6

Teddy, the new GE engines on UP are still 4400 horsepower. They put the “45” in the model, perhaps unwisely, to make the distinction between models.

7

The biggest problem is the 6000 HP engines used were both “clean sheet of paper” designs and had lots and lots of bugs to be worked out. The FDL and 710 engines are really just improved versions of old designs, which is why they are so reliable (relatively, anyway). Even given this, whenever EMD or GE would pu***heir engine design a bit, they always seemed to have some teeting problems. (the 950 RPM 645F engine and 4400 HP FDL are recent examples).

Had Conrail been left alone, they would have purchase a bunch more 5000 HP SD80MACs. They were pretty comfortable with the 20 cylinder 710 and very leary of the new engine designs. There is a market for 6000 HP AC locomotive. Two, 6000 HP AC units can do the work of 3 4000 HP (AC or DC) units in merchandise or intermodal service, but a reliable prime mover needs to be developed before any road goes for them in a big way (CSX was just plain stupid ordering all those 6000 HP GEs IMHO).

8

The problem we are seeing now with the 6000 horsepower locomotives is a repeat of what happened in the late 1960’s early 70’s with the 3600 horsepower locomotives. And in fact a repeat of the mid 1950’s with the 2250/2400 horsepower locomotives. We are again pushing the limits of what our technology can deliver. That always shows up any weakness there might be in the machines.

Alco with the RSD7 and FM with the CPA 24-5 both ended up with locomotives that were huge problems for the buyers. But by the late 1950s 2400 horsepower was easily and reliably obtained. ALCO was able to make the RSD7 reasonably reliable, FM was less successful with the CPA 24-5. (But FM’s 2000 and 1600 HP C liners were much more reliable)

Then when the builders started supplying 3600 horsepower locomotives in the 60’s the railroads started buying and soon found out that the extra horsepower came at a huge maintenance cost. By the time the builders had corrected the major problems the railroads were not interested in anything over 3000 horsepower.

Both times though the builders were able to find ways to correct the problems and apply the solutions to new locomotives. We are well past the time when the standard new road locomotive was 1500/1600/1750 HP, and we are past the time when the standard new road locomotive was 3000 HP. We will see the time when we are comfortably past 6000 HP.

9

Ah yes, but there is somethign even stronger… An EMD “DD”, i heard soem models were 6, 600 HP… could that be true… the UP has a few EMD DD’s.

10

Referance the thread on measuring electrical power on locomotives.

In that thread, you can see that the slower the traction motor turns, the higher amperage. Amperage can, in a ball park fashion, be equated with power, so a diesel electric can start a heavy train, but may not be able to move it very fast. To move the train faster, more horses are needed. (1500 amps to start; 300 amps at full speed) This is know as variable torque.

Steam locomotives and diesel hydralics, however, are constant torque machines. It takes a lot of feet on the rail to start the train, but that same locomotive can operate that train at full speed without additional power. I realize that this is a bit over simplified.

But the point, here, is that the railroads figure something like 5 horses per ton for a pig but only about .8 to 1.0 horse for a drag.

The SP had hydralics during the 1960’s and early 70’s and tried to operate them as if the were diesel-electrics. They burnt up at least one in the middle of a tunnel. When they put an F7 with one DH, they could start a train with the DE (1500 amps to about 2 MPH, where the 4000 HP DH would take over. At this point, the F7 was not producing much pulling power, but the DH was doing the work (speed wise) of 2-3 electric horses to one hydralic horse.

So the railroads will really want 6000 HP DE’s, it’s just as mentioned, they need to be reliable.

As a final note, the EMD 645 and 710 series engines are bored out 567’s. Well, actually, they are cast that way, but the only real difference is the bore, crank shaft and main bearings. The number stands for the Cubic Inch displacement of each cyclinder.

Yes, indeed, the DD-40X was a 66 HP machine with two 3000 HP 645’s turning at a higher RPM.

11

Kevin: it took 2 16-645’s at 3300hp each to do that. they were also prone to cracking the frames, thats why there’s only one left in service and it’s based out of Cheyenne Wyo. with UP’s steam program.
There were 47 6600hp DD40AX’s built. All went to the UP. [8D]

12

On Conrail, typical HP/ton for a van train was 1.75, for merchandise frt it varied, but was close to 1.0 HP/ton.

The typical ruling grade (excluding helper districts) was about 0.8% on most lines.

You need 20#/ton/%grade of tractive effort to get up a hill.

So, if you need 1HP/ton and 20#/ton, the ideal locomotive would have 20# TE/HP
A van train would need 20/1.75 = 11#TE/HP

In general, you want to purchase a bit biased toward TE (higher number) to provide some cushion against stalling, but if you go too far, you are spending money for capability you don’t need. (e.g. buying AC when DC will do or buying six axles when four will do)

A GP40-2 has 51,000/3000 = 17
A B40-8 has 69,000/4000 = 17
An SD40-2 has 83,000/3000 = 28
An SD45-2 has 83,000/3600 = 23
An SD60 has 100,000/3800 = 26
A C40-8 has 109,000/4000 = 27
A C30-7A has 98,000/3100 = 31
An SD70MAC has 147,000/4000 = 36
An SD80MAC has 147,000/5000 = 29
A 6000HP AC unit would have 147,000/6000 = 25

You can see from this, that the high HP four axles have too much HP for the TE to be good for regular merch. svc. and the lower HP AC units have too much TE for their HP to be good for much other than coal drags et. al.

Even the 5000 HP SD80MAC has more TE/HP than an SD60, so, you can see, you really need to get up over 5000 HP for a six axle AC unit to be an ideal replacement for current crop of six axle DC units.

13

Don Oltmann seems to have some first0hand knowledge of some of the locomotives discussed here. I have a follow-up question for Don or anyone else who knows –
How well are the former Conrail SD80MACs performing? Even if’s been good, It would appear that no other railroads think an extra 500 hp is worth the extra complexity of a 20 cylinder prime mover.

Mike

14

Don

.8% where I railroaded was flat land. Most of our grades were above 1.8%, and many of these were in the 2.5+ range for mainline track. One pass had 3.3% grades for a short distance!

For a single (no helper) between Eugene and Dunsmuir operating on a pig timecard, we would have a 4,500 ton train with NO LESS THAN 10,800 HP. If it was to be operated at passenger train speed, we usually put about 15,000 and it still would not exceed 25 mph over some portions of the grade. On that line with the 3.3? 2,750 tons and 9,000 HP (3 SD40’s) just to keep it moving at 11 MPH. 5 SD9’s would do the trick but only get you 6 mph.

15

I don’t know if this topic has been discussed before, but I’ll bring it up anyway.

What is the story with 6000 HP locomotives? It seems like all the new orders are for locos in the 4300 HP range, whether they use AC or DC traction motors. I read stories that both GE and EMD had problems with their new 6000 HP prime movers, and that many of them were in the shop for repairs/upgrades.

What is the real story? Did the builders overestimate the desire of the railroads for these higher horsepower locomotives, or is the problem that they are just not ready for prime time?

Mike Chern

16

Mike,
I brought this subject up four or five months ago and got some good feedback on it. Just getting use to this new format myself. I think there is a way to go back and look at old forum issues, just haven’t figured it out yet. Maybe someone out their can help in figuring out how to find old issues in this new forum. The bottom line is that the 4300/4400 HP engines now are the preferred HP engines and seem to hold up better in all conditions versus the 6000 HP.

Larry

17

4500HP is the new engine, the AC45 that GE’s debuting on UP, and the so called SD89MAC, a 4500HP version of the 90 MAC-H.

18

I believe another factor in the unpopularity of the 6000hp units were issues the UP faced with their Centenial (6900’s) locomotives, the one with two engines per locomotive. The problem was that with so much power in one unit,assigning power to a train was difficult because of reliability issues. If you have two SD40-2 locomotives, and one goes down, you can usually keep the train moving with 1/2 the power. If you have one 6000 hp unit and have a problem, you’re SOL. Plus the large price difference did not justify the extra 1700hp. In addition, servicing one unit takes that much more power out of service.

There are surely more issues, but these are all I remember.

19

The 6000HP EMD’s and GE’s are shop queens. they spend more time there than on the road. That’s why the UP bought 1000 SD70’s [8D] [:D]

I’m sorry but the EMD H engine is junk

20

Teddy, the new GE engines on UP are still 4400 horsepower. They put the “45” in the model, perhaps unwisely, to make the distinction between models.