What's the difference between a Dash 9 and an AC4400CW?

Question

If there are any external differences, is there any way to spot them?

Also, how do you tell the difference between a SD70, a SD80, and a SD90?

Answer 1

Actually believe it or not, the D-9 and AC44 look exactly the same, The only difference between the two is that the dash 9, when it was created was to replace the locomotives the class 1 railroads used for pulling intermodal (double-stack) trains. A dash 9 is capable to move quicker after the engineer puts it into motion, as in there is not as much traction or slag pulling on the train. AC44's are used for hauling more heavy loads such as coal and or grain. AC44's are similar to dash 9's in overall shape though It is designed to start off as well as a dash 9 but for heavier loads.

*Also GE introduced the AC6000 and the AC6043 used for helping trains over large gradients. They are exactly the same as AC44's but they have 1600 more HP to provide the extra push some trains need. CSX uses the 6000's  and UP uses the 6043's.*

The exact words used by manufacturer GE to describe both are as follows:

The DASH 9 is an advanced DC propulsion locomotive that provides improved asset utilization, higher replacement ratios, and lower life cycle costs.

The AC4400 locomotive is a heavy-haul locomotive that delivers world-class tractive effort and unmatched reliability.

Now on to the second part of the question.

If you are referring to the SD70M's used by Union Pacific, Norfolk Southern, and occasionally CSX, They are similar to the SD70MACS used by the BNSF on coal trains. The only exception is with BNSF being the biggest coal hauling railroad in the US, the other three have to use theirs on freight, intermodal, and grain etc... UP and NS use their SD70M's mostly on intermodal but you will find them occaisionly on grain and freight to provide the crew with a "comfort" cab.

SD70MACS on the other hand used by BNSF and CSX are used to haul heavy freight, coal, grain etc... GE introduced the AC4400 to replace the rapidly aging MACS on the BNSF, though BNSF still uses them along with the AC44's and now the low emissions SD70ACe locomotives.

SD80MACS were used by the former class 1 Conrail as a coal hauling locomotive. After the "split/merger" NS and CSX both split Conrail's stock of 80 macs. 80 Macs are about 30' longer than the 70 Macs, and have greater HP than a 70Mac 4250-4000

SD90MACS are used by UP, KCS, and CP. The 90Mac has relatively surpassed the 80Macs on the HP scale 4390-4000. They are the exact same looking except for the HP difference.

Here is a is some pictures of a few of these locomotives from www.railpictures.net

UP AC6000CW: http://www.railpictures.net/viewphoto.ph...

UP SD70M: http://www.railpictures.net/viewphoto.ph...

NS SD70M-2: http://www.railpictures.net/viewphoto.ph...

BNSF SD70MAC: http://www.railpictures.net/viewphoto.ph...

UP SD70ACe: http://www.railpictures.net/viewphoto.ph...

CSX SD80MAC: http://www.railpictures.net/viewphoto.ph...

UP SD90MAC: http://www.railpictures.net/viewphoto.ph...

BNSF Dash 9-44CW: http://www.railpictures.net/viewphoto.ph...

CSX AC4400CW: http://www.railpictures.net/viewphoto.ph...

Answer 2

Both the CW44-9 and the CW44AC widebodys look  very similar..if you look at the left side of the -9 behind the cab you will see an air conditioning unit if so equipped. In this area on the AC the cab appears to extend back below the cab side window about 8 more feet. this compartment contains the 6 really big capacitors for propulsion of the the ac traction motors.There are several other smaller differences, spin filter compartment location, dynamic braking grid cooling vents, other car body door vents...you would really need a good picture of both engines to notice this..But i can tell you behind all that metal there are many differences, but I wont go into that...If the links open for you , you will notice that CW44AC CSXT 31 has high adhesion trucks, CW44-9 CSXT 9026 has standard 3 axle trucks and CW44AC CSXT has steerable trucks. I'll leave the EMD locomotives for someone else, as CSXT only has the SD70....

Answer 3

Often, the only way to tell the SDs apart is by the builders badge-plate.  I'll see if I can dig up some better info.................