Talk:EMD SD70 series

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To-do list	Pending tasks for EMD SD70 series:	(purge cache –  edit this list)
	Pictures of all the variants Purchasers of each type Specifications Mechanical details References!
See also Wikipedia:WikiProject Trains/Todo

Contents 1 SD70MAC variants? 2 Splitting the article? 3 GE compatibility 4 Pictures 5 SD70 Series Rosters/Buyers

[edit] SD70MAC variants?

Are there are different types of 70MACs? The Alaska Railroad purchased two groups of SD70MAC engines. (See near the bottom of this page for engine and model numbers.) The 40xx-series, purchased new in 2000, have flat (flush with the housing) radiator inlet vents and full computer display screens on the conductor's side. The 43xx-series, purchased new in 2004, have slanted radiator vents (i.e. they come out diagonally from the housing, much like the SD90MAC's) and have only a digital speed display on the conductor's side (actually, a sort of downgrade). They also feature air suspension seats in the cab, although the leather isn't as nice and the seats are not quite as comfortable. Also, the computer fans in the cabs of the newer models are much quieter (the loud computer fans of the 40xx-series are a source of annoyance to many train crews).

I almost thought that the 2004 ones were SD70ACe models (because of the wider radiators and the fact that SD70MACs were discontinued due to EPA regulations), but their noses aren't any more angular than the 40xx-series (as the article says), and the model placard inside the cab still says SD70MAC. I know this is a shot in the dark, but does anyone know if there is a sort of intermediate model between the 70MAC and the 70ACe, or if the 70MAC was ever updated or changed slightly? What model would EMD have been producing in 2004? Just curious. cluth 11:25, 23 May 2006 (UTC)

I may have sort of found the answer to my own question buried in the info about the SD70M, where it says: "Starting in mid-2000, the SD70M was produced with SD45-style flared radiators exhibiting a new exhaust system due to the enaction of the EPA's Tier I environmental regulations." Assuming the SD70MAC has followed more or less the same path as the 70M (after all, they were made at the same time, and the only difference is the AC inverters and traction motors), the 70MAC probably received the flared (that's the word I was looking for) radiators at about the same time.

If someone more in the know could confirm that, perhaps could you might add that to the info on the 70MAC?

Actually, what initially made me re-read at the 70M description was the photo of the two UP 70Ms in Dunsmuir: one has the flared radiator, and the other one doesn't. The ARR is the same way, except we have the AC models. Still, there may be a chance that they're actually SD70ACes, though again, they're not labeled as such. cluth 09:40, 24 May 2006 (UTC)

Well, I finally found out what the difference is: the newer 4300-series are still MACs, but they've gotten a power boost (to 4,300 hp) and also contain HEP (head-end power) units to power the passenger cars (thus negating the need for dedicated power cars, which look like baggage cars with exhaust pipes on top). [1] Also, the 70MACs are offered with both Whisper and Safety cab options. [2] The model designation does not change (unlike the DC variants, which are the 70M and the 70I--perhaps because it would become the SD70IMAC?) :-) I will try to update the article accordingly. cluth 22:54, 16 June 2006 (UTC)

Sorry for four posts in a row! :-) I just reread the intro and noticed that it does mention that later-model SD70MACs are rated at 4300 hp. If no one's attached to the current format (and it appears I'm the only one looking at this article...), I'm moving that bit of information to the relevant subsections. I'm also moving the SD70MAC subsection below the SD70I section so I can reference the WhisperCab option in the 70MAC section. If you don't like it, feel free to put it back or change it as needed. cluth 22:54, 16 June 2006 (UTC)

Last post, I promise! I could not find any reference anywhere to the 70I's cab being mounted on shock absorbers. In fact, every other reference online to the 70I (forums, railfan pages, etc.) states that the 70M introduced the wide "North American Safety Cab" (also known as the comfort cab, which is where this article was incorrect), and the 70I introduced the "WhisperCab," which is mounted on rubber gaskets or bushings, not shock absorbers. (I can confirm that the 70MACs with the WhisperCab do NOT have shock absorbers on the cabs--the rocking movement of the cab is exactly the same as the movement of the body going down the tracks at 60mph.) I updated the article to reflect this. If there's any disputes, I'll go back in my history and provide references.

I'm also kind of inferring about the HEP units on later 70MACs. This is based on my own observation of our units and some references from outside sites. cluth 23:40, 16 June 2006 (UTC)

[edit] Splitting the article?

Not sure who originally suggested that the 70ACe and 70M-2 be split, but I vote against it. The locomotives are very much related, and as long as the title of the article is "EMD SD70 series," I think they should all stay under one article. The resulting article on the 70ACe/M-2 would just be a stub, anyway. The article's organization is fine as is.

If I don't hear any objections in a week or two (or a month--whenever I stumble back across this article), I'll remove the split suggestion from the article, especially since there's no rationale posted here. If more information gets added to the article (specs, etc.) that very clearly differentiate the models and make it worth splitting, we can discuss it again at that point. cluth 09:47, 24 May 2006 (UTC)

I feel they should be split. The SD70M-2 (was to be SD70DCe) and SD70ACe share little in common with their prior non-Teir II compliant 70 series denizens:

Different trucks (HTSC/HTCR4 vs HTCRII) and traction motors (D100 vs D90 for DC, EMD/Mitsubishi A3432 vs EMD/Seimens 1TB2630) Different frames (70ACe and 70M-2 share the same frame, AC and DC 70s use different frames) Different radiator core and fan configuration (similar arrangment first seen on the SD89MAC and Phase II SD90MAC), Different FIRE cab (again, similar cab seen on the SD89MAC and Phase II SD90MACs) Different dynamic brake configuration (first seen on the SD89MAC)

ES44ACs have more in common with AC4400Cws than a SD70ACe has in common with a SD70MAC.

Just my thoughts, Robb Fisher, RFDI

Actually while the traction gear/radator/cab/frame have been changed from the earlier 70 series to the later 70 series, there is much that remained the same.

The SD70M-2 uses the AR20/CA7 alternator that was used in the SD70/75 series,

While the SD70ACe uses the TA17 that was used in the SD70MAC.

The computer systems are largely the same, FIRE for the operator screens was used on SD70MAC's since 1997 at least. They still have the EM2000/EMDEC system. The heavy electical switch gear is largely the same on the DC units, however the layout has been changed (again)

They are still 710 powered, one could make a point about the modifications made for Tier 2 compliance but one could also make a point for the Tier 1 compliance mods made earlier.

The air compressor, dynamic brakes, and traction motor blowers are not new and shared with the DC 70 series or 80/90 series.

On the other hand, the ES series shares very little in common with the AC/Dash 9 series, they look about the same on the outside, but GE changed the computers, prime mover, cooling system, heavy electrical system, blowers, main alternator. In fact the only parts a ES shares with the AC/D9 are the trucks and traction motors just about.

Chesapeake 10:37, 28 August 2007 (EST)

[edit] GE compatibility

Is this information true? (Regarding the redesigned cab and windows) I have heard it was just a railfan rumor by several sources.

No it is not true. Close examination of the windows will show that there is no way they are interchangeable. GE glass is a parallelogram, EMD glass is square. This also applies to the 'porkchop' or 'teardrop' glass as well.

Robb Fisher RFDI

[edit] Pictures

Tonight, I added 3 pictures of the SD70 varients. The ACe, the M-2 and the standard cab SD70. Please feel free to rearrange them to fit the article better. 3D jonny 02:20, 17 October 2006 (UTC)

I don't mean to step on anyone's toes, but a scenic, distant nose-shot does little for the article from an encyclopedic viewpoint. I'd much rather see side-on shots that are more technical in nature that show the particular features of the different models. If others agree, I'll make some changes. Akradecki 18:45, 28 December 2006 (UTC)

[edit] SD70 Series Rosters/Buyers

I've added as many of the current operating numbers for the SD70 series as I could find. Some of the article now needs slight rearranging, mainly the pictures (and I dont trust myself to get those in the right order at all).

Did some rearranging in order to eliminate unsightly white space. See my comment above about picture change suggestion. Akradecki 18:46, 28 December 2006 (UTC)