SD40-2,SD40 -3? What's the diffrence?

[bubbajustin]

I'm confused. What is the diffrence between a SD40-2 and a SD40-3, like the DM&E owned? Is it the electronic systems?

[beaulieu]

 An SD40-3 is a non-EMD designation for an SD40 type locomotive fitted with a microprocessor control system. Various aftermaket companies produced retrofit microprocessor kits for SD40 and SD40-2 locomotives. Usually this was done to improve pulling power, emissions, and fuel economy. The original locomotive could be either a SD40 or a SD40-2. This designation is used by some railroads, other common designations used to indicate similar modifications are SD40-2MP, SD40MP, and others. These are not to be confused with SD40-2M which usually indicates an older SD40 or SD45 upgraded to be similar to a SD40-2. All of these designations can mean what ever the railroad wants them to mean. So what NS calls and SD40-3 can be very different from what the DM&E calls a SD40-3. About all that you can be sure of is that it probably has a 16-cyl EMD 645E3 diesel engine, and its probably rated for about 3000 hp.

[nssr9169]

Well I’m not sure if that’s it but I’m guessing you hit it on the head…of course they probably did more to them then just electronics…like rebuild the prime movers or at least tear them down and inspect them…up here the Duluth Missabe and Iron Range rebuilt ex SP SD45T’s with new 16 cylinder 645’s…upgraded electronics(which turned out to be a mess so they have had -2 style electronics put in), and larger compressors…. and they classified them as SD40-3’s I think its more railroad specific to what earned the designation

[wctransfer]

 

SD40-3's are heavily upgraded in the computer area. They all have computer interfaces in the back of the cab panels. Thats the biggest difference, old SD40's that are rebuilt into SD40-3's are a world apart. SD40-3's are more commonly rebuilt SD40's, not SD40-2's, although there are a few.

Alec