SD70M SD75M, whats the diff?

Model Railroader General Discussion (Model Railroader)
1

Whats the difference between the SD70M and the SD75M and are there any differences between them externally?
Mitchell

2

I think that one difference is that while the SD70 has a traction motor blower duct on the left side of the engine only (much like other EMD hood units from the GP35 forward), the SD75 has one on each side.

3

Internally, there is a horsepower difference also. The SD70 is 4000hp while the SD75 is 4300hp.

4

the SD70 was produced before the SD75

5

According to a post by a trusted source in another forum, CN’s SD75 fuel tanks are 16 inches and 400 gallons larger than their SD70’s. Don’t know whether that holds true for all SD70/SD75s, or just CN’s.

Steve

6

THE BASIC difference (on the model) is where the headlight’s are.

The SD-75 was Santa Fe’s version of the SD-70. I’m not sure, but I seem to remember NO other road had SD-75’s except BNSF - which inherited them from the AT&SF.

7

The BNSF SD70MAC has a much Larger Fuel Tank than the SD75M.
Allan.

8

Canadoan National operates a massive fleet of SD75I’s along with a few SD70I’s.

9

That fuel tank thing - The SD70MAC is ‘longer’ than a normal SD70 or SD75 series engine. As far as that traction motor blower on both sides, I have no right hand photos to confirm it. But, I would sort of doubt this(As far as I can tell, this was only done on the GP30). Usually I check for the large square grill below the radiators on the back of the long hood . And as Don mentioned, ATSF/BNSF are the only buyers I am aware of.

Jim Bernier

10

Opps - My mistake. The SD75M’s do have the air duct on both sides - I was thinking about the older ‘laundry chute’ blower ducts on the late ‘50’ line and the the ‘60’ line.

Jim

11

Ontario Northland also has several SD-75i’s that they purchased (new from the factory I believe, but am not sure)

12

It’s funny but back in the day Athearn would have produced one model with an oversized hood and called it an SD70M/70MAC/75M and we would have LOVED IT!!! Personally, I can’t tell the difference looking at the 2 different models (70M and 70MAC)

13

The SD70MAC is much longer than the SD75M. On the SD75M there are two bulges on eather side right behind the cab of the SD75M. On the SD70MAC there is an extended Traction motor blower duct right behind the conductor side. Even though the SD75M has more like 4,300HP compaired to the SD70MAC which has like only 4,000HP. Allan.