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GE "ES44AC" Locomotives

Last revised: February 15, 2024

By: Adam Burns

The ES44AC was General Electric's successor to its very popular AC4400CW model of the 1990s, which sold nearly 3,000 examples between 1994 and 2004.

The ES44AC featured the company's new GEVO prime mover, a 12-cylinder power plant that met the Environmental Protection Agency's (EPA) Tier II standards which went into effect on January 1, 2005.

The AC4400CW had established a new standard in main line locomotives, one that utilized more efficient and powerful AC traction motors in place of DC motors.

Direct current technology had been the industry standard since Electro-Motive's first FT's rolled out of La Grange, Illinois in 1939.  

GE changed the game in the 1980s when it not only surpassed EMD as the industry's top manufacturer but also continually pushed the envelope on locomotive efficiency.

The AC4400CW signaled the end of DC traction motors in main line locomotives although some railroads continued to request them into the early Evolution Series, notably the ES44DC and ES40DC.

GE stopped producing locomotives with DC traction motors after wrapping up production on these locomotives.  Its "ET" Tier IV locomotives are produced only as AC traction variants.


2-039627352836726092909207.jpgCSX ES44AC-H #864 leads empty coal hoppers westbound as the train crests the grade at Alleghany, Virginia on the former Chesapeake & Ohio main line. Loyd Lowry photo.


As Greg McDonnell notes in his book, "Locomotives, The Modern Diesel & Electric Reference: 2nd Edition," the Evolution Series was a seven year program to develop a new engine capable of meeting EPA Tier II emissions standards.

GE's tried and true engine, the FDL, was able to meet EPA's Tier 0 (1973-2001) and Tier I (2002-2004) standards.  These had originally been established in December, 1997 and made retroactive to locomotives produced after 1973.

With more stringent standards under Tier II emissions set to take effect on January 1, 2005, GE realized it needed a new engine.  The company no longer felt the FDL could do so without seriously sacrificing performance and efficiency.

GEVO Prime Mover

Following hundreds of millions of dollars in research and development, GE unveiled its new GEVO prime mover in March, 2002 when testbed #2005 rolled out of Erie.

This engine was a 12-cylinder power plant that could still produce the same 4,400 horsepower as its predecessor.  In addition, GE engineers had designed the GEVO to meet future emissions standards, notably Tier III (January 1, 2012) and Tier IV (January 1, 2015).

By the 2000s, GE was the industry standard in locomotive production.  The company had surpassed EMD long ago, thanks largely through its efforts of employing technology to lower operational costs and improve locomotive efficiency.

20359823752368528736982860207.jpgUnion Pacific ES44AC #5611 leads an intermodal freight over Cajon Pass as the train rounds Sullivan's Curve. Loyd Lowry photo.

As a result, railroads were willing to purchase its latest products almost immediately.  Most notably was GE's AC6000CW of the 1990s, which could produce 6,000 horsepower.

These monsters featured a redesigned engine, the 7HDL, a product built in conjunction with renowned engine manufacturer Deutz-Motoren Werke Mannheim (MWM) of Germany.

Ultimately, this power plant ran into reliability issues while railroads discovered a single 6,000 horsepower behemoth was too much for their needs.

However, this did not stop Union Pacific from placing orders immediately, even before the new engine was ready for production by acquiring "Convertible" variants that sported a standard 4,400 horsepower 7FDL engine.

The idea here was that these locomotives could later be refitted with the  new 7HDL once it was ready (in the end, this never occurred).

In the case of the ES44AC, General Electric produced some 35 examples of what could be described as demonstrators.  The locomotives sported the liveries of the respective railroads on which they tested, similar to its approach with the "Dash 8" line.

These demonstrators were impossible to distinguish as testbeds but remained wholly-owned GE products during the 2003-2004 trials and ultimately were purchased by their respective railroads.

Once again, Union Pacific was the first to test GE's latest AC traction product (what GE initially dubbed as "A.C. V12 Tier II Preproduction"), acquiring five of the locomotives in early 2003 (#5695-5699).  Next, BNSF acquired a whopping thirty units between August, 2003 and January, 2004 (#5718-5747).

Data Sheet

Entered Production3/2002 (General Electric #2005)
Years Produced3/2002 - 10/2019
GE ClassES44AC
EngineGEVO-12 (12 cylinder)
Engine BuilderGeneral Electric
Length73' 2"
Height (Top Of Rail To Top Of Cab)15' 5"
Width9' 11"
Weight416,000 - 432,000 Lbs
Fuel Capacity5,000 Gallons
Air Compressor3CDC (Westinghouse)
Air Brake Schedule26L (Westinghouse)
Truck TypeHi-Ad Bolsterless Or Steerable (GE)
Truck Wheelbase13' 2"
Wheel Size42"
Traction MotorsGEB13 (6), GE
Traction AlternatorGMG205, GE
Auxiliary AlternatorGYA30A, GE
MU (Multiple-Unit)Yes
Dynamic BrakesYes
Gear Ratio83:20
Tractive Effort/Starting183,000 Lbs
Tractive Effort/Continuous166,000 Lbs at 13.7 mph
Top Speed70 mph

Production Roster

(Total Built = 3,764)

Owner Road Number Serial Number Order Number Completion Date Quantity
General Electric (Demo)20055368119393/20021
Union Pacific5695-569653878-53879195212/20022
Union Pacific5697-569953976-5397819522/20033
Burlington Northern Santa Fe5718-574754400-5442919628/2003-1/200430
Union Pacific5354-555355510-5570919821/2005-7/2005200
Canadian Pacific8700-873955956-55995199010/2005-11/200540
BNSF Railway5748-579755996-5604519887/2005-9/200550
Union Pacific53535614619828/20051
BNSF Railway5798-583756156-5619519889/2005-10/200540
Canadian Pacific8740-875956340-56359199011/2005-12/200520
Union Pacific5248-534756592-5669119982/2006-8/2006100
BNSF Railway5844-604356692-56891190010/2005-7/2006200
BNSF Railway6044-608657019-5706119008/2006-9/200643
BNSF Railway6087-613857104-5715519009/2006-10/200652
Canadian Pacific8760-883957156-5723520039/2006-12/200680
Canadian Pacific8840-885957236-5725520035/200720
Kansas City Southern4650-467957486-57515191211/2006-1/200730
Union Pacific7600-769957536-5763519136/2007-9/2007100
BNSF Railway6139-623857636-5773519001/2007-4/2007100
Union Pacific7700-779958008-5810719131/2007-6/2007100
Kansas City Southern4680-472958128-5817719199/2007-10/200750
CSX Transportation700-799 (ES44AC-H)58294-58393192410/2007-12/2007100
Canadian Pacific8860-889958446-5848519801/200840
Arcelor Mittal (Cartier Railway)301-30258714-5871519232/2011-3/20112
General Electric (Demo)20125941819377/20081
CSX Transportation800-899 (ES44AC-H)58486-5858519241/2008-5/2008100
Union Pacific7345-746958588-5871219531/2009-7/2009125
Norfolk Southern8024-804858861-58885197910/2010-11/201025
Union Pacific7800-792458946-5907019314/2008-6/2008125
Kansas City Southern4730-475959071-5910019384/2008-6/200830
Iowa Interstate500-51159419-5943019477/200812
CSX Transportation900-949 (ES44AC-H)59431-5948019487/2008-9/200850
Norfolk Southern8000-802359504-5952719579/2008-10/200824
Iowa Interstate512-51359528-5952919518/2009-9/20092
CSX Transportation950-997 (ES44AC-H)59530-59577195112/201148
BNSF Railway6239-629959578-59638196010/2008-11/200861
BNSF Railway6400-641559639-59654196012/200816
BNSF Railway6416-643859892-5991419528/200923
BNSF Railway6300-639959915-6001419648/2009-11/2009100
Norfolk Southern8049-809060233-6027419791/2011-3/201142
Union Pacific7470-752960465-6052419844/2011-8/201160
Ferrocarril del Sureste (Ferrosur)4709-472260607-6062019877/2011-9/201114
Seaview Transportation1912, 1982, 198660621-60623198910/2011-11/20113
Kansas City Southern4765-478960624-60648199211/2011-12/201125
Kansas City Southern de México4760-476460649-60653180112/20115
Canadian Pacific8900-896060654-6071419808/2011-11/201161
Canadian Pacific9350-937960715-6074419801/2012-2/201230
Norfolk Southern8091-811560745-6076919911/2012-3/201225
Union Pacific7925-805160996-6112219953/2012-9/2012127
CSX Transportation3000-3064 (ES44AC-H)61123-6118719963/2012-6/201265
Kansas City Southern4790-480961246-6126519929/2012-10/201220
Canadian National2800-282461266-61290180611/2012-12/201225
Citicorp Railmark (CREX)1201-121561406-6142019399/2012-11/201215
CSX Transportation3065-3174 (ES44AC-H)61596-6170518122/2013-11/2013110
Norfolk Southern8116-814061706-6173018149/2012-12/201225
Norfolk Southern8141-816561811-6183518148/2013-9/201325
Union Pacific8052-811161868-6192718136/201360
Citicorp Railmark (CREX)1301-135061944-6199318218/2013-12/201350
Canadian National2835-286461994-62023182012/2012-1/201330
Union Pacific8112-8171 (ES44AC-H)62457-6251618273/2014-5/201460
Union Pacific8172-823862587-6265318275/201467
Canadian National2865-290962654-6269818319/2013-11/201345
Citicorp Railmark (CREX)1401-143562723-6275718336/2014-8/201435
Union Pacific8239-8267 (ES44AC-H)62813-62841182712/201429
Canadian National2910-293962842-62871183112/2014-1/201530
Canadian National2940-295062893-62898, 63381-6338518312/2015-3/201511
CSX Transportation3175-3249 (ES44AC-H)62899-6297318447/2015-12/201575
Iowa Interstate514-51662986-62988183711/20143
Union Pacific2520-2569 (ES44AC-H)63331-6338018462/2015-4/201550
Kansas City Southern de México4870-489463386-6341021074/2015-7/201525
Canadian National2951-297563414-6343821083/2015-4/201525
Citicorp Railmark (CREX)1501-152563833-63857185412/201525
Norfolk Southern8166-8168 (ES44AC-TC4)64090-6409218585/20163
Canadian National2976-298364403-64410185110/2016-11/20168
Cerrejón (Columbia)1015-102564235-64242, 66304-66306-11/2012, 6/2015, 12/202011
Norfolk Southern8169-818464608-6462318142/2017-3/201716
Canadian National2984-2999 (ES44AC-TC4)64635-64650188010/201716
Canadian National3800-3805 (ES44AC-TC4)64651-64656188011/20176
Canadian National3806-383564744-64773-5/2018-5/201930
Canadian National3836-387565818-65857-1/2019-6/201940
Canadian National3876-389566068-66087-5/2019-7/201920
Iowa Interstate517-51966132-6613418378/2019-10/20193
Canadian National3896-391266235-66251-10/2019-1/202017


  • McDonnell, Greg. Locomotives: The Modern Diesel & Electric Reference, 2nd Edition. Buffalo: Boston Mills Press/Firefly Books, 2015.
  • Solomon, Brian.  GE and EMD Locomotives:  The Illustrated History.  Minneapolis:  Voyageur Press, 2014.

20352938273572876289092709.jpgCSX ES44AC-H #3233 leads the company's Office Car Special eastbound past the former Chesapeake & Ohio yard and coaling tower at Ronceverte, West Virginia. Loyd Lowry photo.

BNSF also went on to acquire the first production ES44AC's (#5748-5837) and ES44DC's (#7650-7799) between January and July, 2005.

General Electric has largely standardized its road-switcher carbodies since the 1990s featuring the North American Safety Cab (wide cab), followed by a long carbody, and wide, rear flared radiators.

As such, at first glance it is difficult to distinguish an ES44AC from the earlier AC4400CW; both are 73' 2" in length, sport an "Aux Cab" on the left side of the carbody for A.C. traction circuitry, and are equipped with either GE's HiAd or Steerable truck.

Perhaps the only reliable identifier, aside from the road numbers themselves, is a small bulge along the top of the radiator wing which is not present on AC4400CW's.


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!