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GE "AC4400CW" Locomotives

Last revised: June 4, 2023

By: Adam Burns

The AC4400CW was basically a variant of the C44-9W in that it featured AC (alternating current) traction motors instead of the more traditional DC (direct current) traction motors.

Different from the traditional DCs, AC traction motors are much more simple, reliable, and easier to maintain albeit they costs far more.

Aside from their reliability and simplicity they provide phenomenal pulling power and are ideal for use in heavy drag service hauling freight over stiff grades.

Because of this, and the need for power at the time, railroads loved the model and it went on to become the most successful present day locomotive.

They have since been replaced by GE's newer ES44AC model but almost all of the AC4400s remain in revenue service on every Class I in North America except for CN and NS (which did not purchase the model).

As such, if you are a railfan roaming the main lines in the United States or Canada there is a high probability that you will run across one at least once. 

Note that the model's days may be growing short.  Many are more than 20 years old and as new designs are cataloged the 4400's are being pushed down the roster. 

In addition, some Class I's have opted to rebuild older units in their fleet instead of purchasing new.  This has included some 4400's, such as on Union Pacific where a handful are now classified as C44ACM's.


239582839587213598269028979038.jpgCSX AC4400CW #503 eases its way south on the Ohio River Subdivision at Sistersville, West Virginia on May 5, 2002. Wade Massie photo.


The AC4400CW was General Electric's answer to Electro-Motive's SD60MAC released in June, 1991.  Interestingly, EMD's test was successful with four demonstrator units ultimately produced for Burlington Northern, #9500-9503. 

However, the builder never cataloged a model with alternating current traction motors until its SD70MAC two years later.  In the mean, GE recognized the market for AC motors had arrived and began development on what became the AC4400CW.

For GE it was the first locomotive in its catalog with AC traction motors and railroads quickly recognized the effectiveness of this new technology. 

By the early 1990s the company was already the top manufacturer thanks to the success of its Dash 8 line.  These locomotives were the first to feature microprocessors and a game changer in operational efficiency. 

The Dash 9 series continued its predecessor's accomplishments and boasted the latest technological developments such as split cooling, electronic fuel injection, and high adhesion (or HiAd) truck.

Aux Cab

The AC4400CW was nearly identical to the C44-9W in outward appearance and inward components.  Its notable spotting feature, as Greg McDonnell notes in his book, "Locomotives, The Modern Diesel & Electric Reference: 2nd Edition," was the addition of a large box just behind the left side of this cab.

This so-called "Aux Cab," as GE described it, held all of the A.C. traction circuitry.  The basic premise of the AC4400CW's is that its inverters held in this cabinet (the original models featured six "Gated Turn On" devices per inverter, or 36 in all) convert DC power from the main alternator to three-phase AC power used by the traction motors.

Interestingly, AC44's built after 1998 replaced these GTO's with what GE called Integrated Gate Bipolar Transistors or IGBT's.  This new technology essentially made the "Aux Cab" irrelevant.

One final upgrade was the introduction of GE's steerable truck.  Electro-Motive, once again, had pioneered this technology with its HTCR-II. 

While industry experts often view EMD's as superior, which helped it sell thousands of SD70 series models in the 1990s and 2000s, GE created a radial version of its HiAd in 1996 that has proven satisfactory.

GE's model designation for the AC4400CW was as follows:

  • "AC" referred to alternating curren

  • "4400" listed the horsepower rating

  • "C" noted the unit as having C-C trucks n(three axles per truck)

  • "W" described its wide, North American Safety Cab

Officially, the AC4400CW went into GE's catalog in the summer of 1994 and became so successful it remained in production until the company unveiled its new design, the ES44AC which was part of its new Evolution Series, in early 2005.

Data Sheet

Entered Production6/1993 (General Electric #2000)
Years Produced6/1993 - 11/2007
GE ClassAC4400CW
Engine7FDL16 (16 cylinder)
Engine BuilderGeneral Electric
Length73' 2"
Height (Top Of Rail To Top Of Cab)15' 4 2/3"
Width9' 11"
Weight408,000 - 432,000 Lbs
Fuel Capacity5,000 Gallons
Air Compressor3CDC (Westinghouse)
Air Brake Schedule26L (Westinghouse)
Truck TypeHi-Ad Bolsterless (Steerable Trucks Optional)
Truck Wheelbase13' 2"
Wheel Size42"
Traction Motors5GEB13 (6), GE
Traction AlternatorGMG196 or GMG192, GE
Auxiliary AlternatorGYA30A, GE
MU (Multiple-Unit)Yes
Dynamic BrakesYes
Gear Ratio83:20
Tractive Effort/Starting180,000 Lbs
Tractive Effort/Continuous145,000 Lbs at 13.7 mph
Top Speed75 mph

Production Roster

(Total Built = 2,972)

Owner Road Number Serial Number Order Number Completion Date Quantity
General Electric (Demo/Testbed)20004753018506/19931
CSX Transportation9100-910247581-4758318516/19943
Union Pacific9997-999947634-4763618508/19943
CSX Transportation9103-911348031-48041185310/199411
CSX Transportation15-3048042-48057185310/1994-12/199416
Chicago & North Western8801-883548169-48203185511/1994-12/199435
CSX Transportation31-11548384-4846818531/1995-4/199585
Canadian Pacific9500-958248795-4887719658/1995-10/199583
Southern Pacific100-30248473-4867518574/1995-7/1995203
Southern Pacific303-37848719-4879418577/1995-10/199576
General Electric (Demo/Testbed)44004887818908/19951
Union Pacific6838-688748925-48974186610/1995-11/199550
CSX Transportation116-17348978-4903518591/1996-5/199658
CSX Transportation201-22549036-4906018595/1996-7/199625
Union Pacific6738-683749185-4928418703/1996-6/1996100
CSX Transportation226-28049514-4956818697/1996-12/199655
Union Pacific6550-669949788-4993718743/1997-7/1997150
General Electric (Demos)*4000-400949973-4998218813/199710
Canadian Pacific9583-968350089-5018918809/1997-1/1998101
CSX Transportation281-30150266-5028618828/1997-9/199721
Union Pacific7080-710050498-50518188910/1997-12/199721
CSX Transportation302-34150520-5055918902/1998-4/199840
Transportación Ferroviaria Mexicana (TFM)2600-264950576-5062518915/1998-7/199850
Canadian Pacific8500-858050826-5090619922/1998-12/199881
Union Pacific7101-713751025-5106118956/1998-8/199837
CSX Transportation342-36651070-51094189010/1998-11/199825
CSX Transportation367-39051384-51407190211/1998-12/199824
CSX Transportation391-42151408-5143819028/1999-10/199931
Union Pacific7138-726251444-5156819114/1999-9/1999125
Union Pacific6995-699951569-5157319119/19995
Union Pacific7263-729251574-5160319119/1999-12/199930
Kansas City Southern2000-204952048-52097191811/1999-12/199950
Union Pacific7293-729752098-52102191112/19995
Union Pacific6525-654952127-52103 (Reversed)19204/2000-1/200025
Burlington Northern Santa Fe5600-560252128-5213019169/19993
Ferrosur (Mexico)4400-441452444-5245819231/2000-2/200015
Union Pacific6430-652452582-52488 (Reversed)192011/2000-4/200095
CSX Transportation422-49652703-5277718907/2000-9/200075
Transportación Ferroviaria Mexicana (TFM)2650-267452778-5280219138/2000-11/200025
Union Pacific5700-576953096-53165 (Not In Sequential Order)1937/19461/2001-4/200270
CSX Transportation497-54653166-5321519354/2001-9/200150
Canadian Pacific8600-865053337-5338719329/2001-10/200151
Québec Cartier Mining18-2953388-53399193311/2001-6/200212
CIT Group1001-102553458-53482194311/2001-12/200125
Union Pacific5771-586353537-5363019421/2002-4/200293
Union Pacific5864-588853631-5365519429/2002-12/200225
CSX Transportation547-55653671-5368019453/200210
CSX Transportation557-59953682-5372419456/2002-8/200243
CSX Transportation5101-512253725-5374619498/2002-9/200222
Canadian Pacific9700-974053930-53970195410/2002-1/200341
Union Pacific5889-591353979-54003194211/2002-12/200225
Union Pacific5914-598154104-5417919551/2003-5/200368
Burlington Northern Santa Fe5603-565354190-5424019594/2003-5/200351
Ferrosur (Mexico)4415-442954430-5444419636/200315
Canadian Pacific9750-978454445-5447919657/2003-9/200335
Union Pacific6023-605954714-54733 (Not In Sequential Order)19689/200337
Burlington Northern Santa Fe5654-571754615-5467819701/2004-4/200464
Burlington Northern Santa Fe5838-584054679-5468119703/20043
Union Pacific5982-602254480-5452019689/2003-10/200341
Union Pacific6060-608154734-5475519713/2004-4/200422
Canadian Pacific9800-984055070-5511019764/2004-6/200441
Union Pacific5554-569455147-5528719776/2004-12/2004141
CIT Group1026-105955425-5545819799/2004-11/200434
Ferromex (Mexico)4550-457455475-55499198111/2004-12/200425
Ferrominera Orinoco (Venezuela)1058-105955500-55501199112/20042
Ferrosur (Mexico)4430-443755502-55509198512/20048
Quebec North Shore & Labrador415-42156147-56153199212/20057
Québec Cartier Mining13-1757062-5706620014/20065
Carbones de Cerrejón (Colombia)10145708720028/20061
Quebec North Shore & Labrador422-42657088-57092190510/2006-11/20065
Québec Cartier Mining11-1258444-58445192311/20072

* Became Union Pacific #7000-7009.


  • Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.
  • McDonnell, Greg. Locomotives: The Modern Diesel & Electric Reference, 2nd Edition. Buffalo: Boston Mills Press/Firefly Books, 2015.
  • Solomon, Brian. American Diesel Locomotive, The. Osceola: MBI Publishing, 2000.
  • Solomon, Brian.  GE and EMD Locomotives:  The Illustrated History.  Minneapolis:  Voyageur Press, 2014.
  • Solomon, Brian. GE Locomotives: 110 Years Of General Electric Motive Power. St. Paul: MBI Publishing, 2003.


By that time GE had sold a mind-boggling 2,972 units to every North American Class I except Norfolk Southern and Canadian National.

For lines like Union Pacific and CSX, the two biggest buyers of the AC4400CW, the locomotive has been an incredible asset in the movement of heavy freight, notably coal drags through Wyoming's Powder River Basin and West Virginia's Appalachian coal fields.

Today, while their carbody is virtually identical to other, similar GE models like the C44-9W, likely every other locomotive you will see pulling a freight is a AC4400CW or ES44AC as nearly all remain in active revenue service on Class I railroads. 


Wes Barris's SteamLocomotive.com is simply the best web resource on the study of steam locomotives. 

It is difficult to truly articulate just how much material can be found at this website. 

It is quite staggering and a must visit!