EMD SD70 series official thread (EXCEPT for ACe version)

[jlr3266]

This is a very informative thread. So, SD came about with the first six axle engines and has nothing to do with actual use, as in "Special Duty" versus "General Purpose"?

[MEC407]

This is a very informative thread. So, SD came about with the first six axle engines and has nothing to do with actual use, as in "Special Duty" versus "General Purpose"?

Correct. As far as Class I railroads today are concerned, six-axle units are considered to be "general purpose" units.

[jlr3266]

This is a very informative thread. So, SD came about with the first six axle engines and has nothing to do with actual use, as in "Special Duty" versus "General Purpose"?

Correct. As far as Class I railroads today are concerned, six-axle units are considered to be "general purpose" units.

Thanks. So, as stated before, SD should be Six Damn axles and GP should be Got Plain four axles.

[Sir Ray]

This is a very informative thread. So, SD came about with the first six axle engines and has nothing to do with actual use, as in "Special Duty" versus "General Purpose"?

Well, to be fair, when the GP7 came out (about the time of the F7, or ...Freight unit 7 series ), it was meant as a (well, to EMD, the) General Purpose freight locomotive (which it, and it's many 4 axle brethen, served as until the 1970s). Special Duty locomotives, as their name implies, were for special purposes such as hump engines, heavy drag haulers, or light-load lines (where spreading roughly the same weight over 6 axles as opposed to 4 led to a much lower per-axle loading, better for branch lines having lighter track but large radius curves). Hence 2,724 GP7s vs 188 SD7s.
(OK, yeah, the SD7 was in production for 2 years vs 5 for the GP7, so for a better comparison: 4092 GP9s vs 471 SD9s - BTW, F production was getting low at this point: 87 F9As and 154 F9Bs)
And the granddaddy of them all, the E units? Eighteen Hundred HP. (and only 4 powered axles, albiet they had 6 axles all total)

(I was pulling all this from Wiki, but actually I learned it years ago from my well worn copy of "Diesel Locomotives: The First 50 Years")

[jgallaway81]

Okay.. I'm interested in a VERY specific model of diesels (I'm a steam guy, sorry)

As a newly promoted locomotive engineer, I've gotten to run almost every model of engine on NS... except the F units of course.

Through it all, one engine has remained my favorite... the EMD SD-70M-T1.... prior to the SD70ACe and SD-70M-2, there was a model that used a different version of the FIRE cab and an SD-45-style flared radiator.

The only way to tell the SD-70M-T1 from a regular SD-70M (unless you can see the difference) was the badgeplate inside the cab added "T1" to the model designator... I'm assuming that referenced "Tier-1 compliance"

For pics, check railpictures.net for the NS 2591-2648 (here is a good shot: http://www.railpictures.net/viewphoto.p ... 224&nseq=6)

Does anyone know how many of these units were constructed? I dont just mean the NS ones, I have seen a couple UP units, but thats it.

I'd like to get as much info on this engine style.

If you are curious, my interest in this engine is as a railfan... looking at the SD-70M-T1 gives me the same feeling of brute strength combined with speed and sure-footedness as looking at pictures of C&O or NKP 2-8-4 Berkshires... I can't explain it, I just know that I like the design.

Since it seems that very few units of this style were built, can anyone xplain the radical change in design between the 70M-T1 and the 70M-2? (I mean the cab.. I know the radiator change was due to TierII cooling.

Thanks for your time...

[BlackDog]

As an engineer, I am sure you will learn to hate them soon enough.

[jgallaway81]

Well, I have yet to get throttle time on this model.

But I have heard they are worse then the 70M-2 even.


Personally, I just like the design... I think it looks cool.

[tomjohn]

As Mr. Gallaway states in his post , As a newly promoted locomotive engineer, I've gotten to run almost every model of engine on NS... except the F units..

Now to place my opinion on this topic. As a railway enthusiast I am curious to see how these new EMD SD 70 series offerings will fair from the older EMD SD70, SD75, SD70M, SD70I,SD75I and SD 70-M 2 offerings. Not to have the EMD SD 50 SD60,SD 60I and the EMD SD90 series be forgotten.
There is some of the general public will say that every thing looks alike now.My theory is this that some lack creativity,this also includes companies!

Tom

[QuietGuy]

The T1 locomotives are EUI while the previous, original order were MUI (fuel injector types). The T1's had to be made to meet the EPA Tier 1 emission limits. This came about after the initial SD-70M orders were going into production. Towards the end of the run, the last third of the order would be delivered after the date that the new emissions standards were required, so those last units had the EUI engine. UP was not happy about that since the original concept was the reliability of the MUI engine - the EUI's had had problems. Fortunately the EUI's on that order were even more reliable than the MUI's, possibly because every problem that could have occurred were fixed on the CN & BNSF locomotive orders that had EUI engines, and those corrections were included on the UP SD-70 T1 engines.

[mbta1051dan]

Moderators note: I am combining all of the random SD-70ACE posts, questions and musings into this single SD-70ACE topic. Please use this topic, for all of your SD-70ACE questions, comments and concerns. Thanks to all for contributing, and enjoy the streamlined search, with a new single source for info. Regards



Original question posted by Dan:

Hi,

I was wondering how HEP was generated on Alaska Railroad's SD70MAC-HEPs. They look like pretty much any other flared-rad SD70 out on the road, and I don't see that smaller diesel exhaust stack on the back of the unit. Is it inverter-HEP like the PL42s?

-Dan

[DutchRailnut]

one traction inverter is used for HEP reducing unit to 50% traction power.

[mbta1051dan]

Oh so then how come on the you tube vids of them, they're pulling a very long train singlehandedly and look like they have no trouble doing it, and the prime mover idles at the same RPM as the frieght model?

-Dan

[DutchRailnut]

They do not always use the HEP, sometimes a HEP car or the cars own generators are used.

[tomjohn]

Are there complete drawings of ALASKA RAILROAD'S SD70MAC HEP's,does anyone have the courage to produce these yet?

[NV290]

Are there complete drawings of ALASKA RAILROAD'S SD70MAC HEP's,does anyone have the courage to produce these yet?

What?