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[Anonymous]

Just as railpac started his Alco question thread, I thought I would start an EMD question and answer topic. If you have any questions about EMD products, ask them here!

[Anonymous]

1. What is the difference between an SD70 and an SD75?

2. Why do Canadian EMD Locomotives have an I at the end of their name (Ex: SD75I)?

BahnMan1

[Anonymous]

Answer 1: SD70Ms (phase 1) and SD75Ms are identical on the left side, but on the right side there is a bulge just behind the cab. The only SD75Ms were built for Santa Fe and BNSF, and they don't have any SD70Ms, so that makes it easier. Phase 2 and Phase 3 SD70Ms have been purchased by UP and NS. Both engines will be out of production on January 1st, 2005 (or earlier) because that's when the EPA emissions standards come in to effect. The engines will probably be superceded by the SD70ACe.

Answer 2: The I actually is for Isolated Whisper Cab. It just seems that Canadian railroads happen tohave them. SD60Is were bought by Conrail, SD70Is, CN SD75Is, CN. During SD70MAC production, EMD made the whisper cab standard on all engines, these SD70MACs are known as SD70MAC-I's. So all SD80MACS and SD90MACS have the Isolated cab. SD70ACes have a whole different cab and nose. You can distinguish an I from an M (i.e. SD60M and SD60I) by looking at the nose. I's have a seam (which appears as a black line) thought the nose separating the nose and cab components, thus quieting down the cab. M's don't have this feature.

[CSSHEGEWISCH]

Flexicoil trucks were offered as an option on the SW1000 and SW1500. Were they also available for the SW1001?
Aside from the sheet metal, are there any mechanical or electrical differences between the various MP15 models and the corresponding GP15's?

[Anonymous]

Answer 1: Although I think Flexicoil trucks were availible on the SW1001, no railroads that I know of bought SW1001s with Flexicoils.

Answer 2: Ironically, MP15s are heavier than GP15s. Obviously, GP15s carry more fuel than MP15s. Finally, GP15s have a toilet, MP15 don't [;)]

[csxengineer98]

why are the dynamic brakes on the 70 & 80macs so weak compaired to the superior GE dynamic brake

[csxengineer98]

opps...left out something...when i say GE, im talking -8s -9s and the ACs

[Anonymous]

Since I'm a railfan and not an engineer, I need a bit more info. Could you please tell me if SD40-2 dynamic brakes are better than SD70MAC or 80MAC dynamic brakes?

[Anonymous]

Any Online Wide Cab Locomotive Manuals I know yjeh have ones for SD40-2 but any SD70M Types please let me know

[Anonymous]

I couldn't find any.

[Anonymous]

I come from New Zealand
I want to know more information about SD60, 70 ,75,80 ,90 etc
what is MAC , M , I ?
Might extra if need more horsepower ? that right

[M636C]

Mark,

I think you might have mentioned in the SD70/SD75 comparison that the SD75 is 4300 HP and the SD70 is 4000 HP. This is acheived by running the 16-710G3 at 950 rpm rather than 904 rpm maximum speed. When the Santa Fe units first came out some of them were set to give 4500 HP at 1000 rpm, but this might not still be the case. I note that EMD are putting the 4300 HP engine in the SD70ACe, which makes it the equivalent oof the 710 engine SD90MAC. So now we have SD70, SD75 and SD90 models all with the same engine and power rating.

In the question of dynamic brakes, EMD vs GE, a couple of things come to mind. The DC locomotives, the GE Dash8s and Dash9s, have slightly heavier motors in the GE752 compared to the D87 in EMD DC locomotives, and this would allow heavier braking current in the GE locomotives. I don't know enough about the relative qualities of the AC motors between GE and EMD to say why a GE could have better dynamic performance, but it is possible that the different AC inverter arrangement might affect dynamic braking. In the GE units, each motor has its own inverter, independent of all the others, so there are six inverters on an AC4400CW. EMD, who use the German Siemens equipment, have one inverter per truck, ie each inverter feeds three motors under power, but three motors feed each inverter in dynamic brake. Since more power is involved in dynamic braking, it is possible that current limits in the EMD inverters might limit their dynamic braking performance compared to the GE, where there may be slightly more reserve in each inverter to take more current from the individual motor.

And for my neighbour in New Zealand who is using the number of a rebuilt U26C, M stands for "Modified", in this case, the wide nose cab (much like DXR 8007's cab), and AC is for (variable voltage, variable current) alternating current, using inverters to change from DC, which is in turn rectified from three phase AC in the locomotive's alternator.

Peter

[Allen Jenkins]

I say Goodaye to ya! dxr8007. The published Kalmbach books hold the local body of knowledge upon these USA locomotives you asked about, probably the most info you can get on the group, and these forums, these guys like to tra***hrough the particulars on a regular basis, feel free to ask questions, step aside and follow closely! You also have some South Pacific motive power to add a few Entries on, like the six axle carbody type locomotive with three radiator fans, and rear mounted Dynamic brake resistor cooling fan that I saw on some of the www.auran.com links the other night. Enjoy your hobby! Backyard said that gooday!

[Anonymous]

Thank you M636C and Allen Jenkins for infromation about EMD SD 60, 70 ,75, 80 ,90 now I will remember this infromation EMD SD

[Anonymous]

Which company Railroad will buy new SD70ACe ? BNSF or UP or other company Railroad