The GE AC44C6M is an AC-traction

diesel locomotive A diesel locomotive is a type of railway locomotive in which the prime mover (locomotive), power source is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is con ...

, rebuilt from

GE Transportation GE Transportation is a division of Wabtec. It was known as GE Rail and owned by General Electric until sold to Wabtec on February 25, 2019. The organization manufactures equipment for the railroad, marine, mining, drilling and energy generatio ...

Dash 9 locomotives. AC44C6M rebuilds have been done by GE (now

Wabtec Westinghouse Air Brake Technologies Corporation, commonly known as Wabtec, is an American company formed by the merger of the Westinghouse Air Brake Company (WABCO) and MotivePower in 1999. It is headquartered in Pittsburgh, Pennsylvania. Wab ...

), American Motive Power, Inc., and

Norfolk Southern Railway The Norfolk Southern Railway is a Class I freight railroad operating in the Eastern United States. Headquartered in Atlanta, the company was formed in 1982 with the merger of the Norfolk and Western Railway and Southern Railway. The comp ...

's Juniata and Roanoke Shops, starting in September 2015. The AC44C6M retains the 16-cylinder 7FDL-16

prime mover Prime mover may refer to: Philosophy *Unmoved mover, a concept in Aristotle's writings Engineering * Prime mover (engine or motor), a machine that converts various other forms of energy (chemical, electrical, fluid pressure/flow, etc.) into ener ...

used in the core locomotive prior to rebuilding, but replaces the Dash 9's DC traction motors with

alternating current Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in w ...

GE 5GEB13B7

traction motors A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric or hydrogen vehicles, or electric multiple unit trains. Traction motors are used in electrically powered railway vehicles (electric multiple u ...

. Externally, Norfolk Southern's Dash 9-40Cs received new wide-nosed cabs, and all rebuilt locomotives have a new hood front section with a new inverter cabinet behind the cab, while retaining the underframe and engine and radiator compartments of the original Dash 9 units. Rebuilding an old Dash 9 locomotive into an AC44C6M costs only 50-60% that of purchasing a brand new AC locomotive. Wabtec claims a 17% improvement in

fuel efficiency Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical energy, chemical potential energy contained in a carrier (fuel) into kinetic energy or Mechanical work, w ...

, 30% improvement in reliability, and a 55% improvement in haulage capability.

History

BNSF BNSF Railway is the largest freight railroad in the United States. One of six North American Class I railroads, BNSF has 36,000 employees, of track in 28 states, and over 8,000 locomotives. It has three transcontinental routes that provide ...

was the first railroad to order locomotive rebuilds with an order for 21 AC44C4Ms that were delivered in September 2015. These were followed shortly by Norfolk Southern's AC44C6M's, which were first delivered at the end of 2015, and rebuilt from their Dash 9-40C locomotives. Norfolk Southern is the largest operator of the AC44C6M, with over 600 locomotives rebuilt as of 2022, and a further 330 by 2025. All of their Dash 9-40C units, and significant numbers of their Dash 9-40CW units have been rebuilt into AC44C6Ms. The railway plans to rebuild all of its remaining Dash 9–40CW units into AC44C6Ms. Norfolk Southern's AC44C6M locomotive features a new under-floor air conditioner, cab signals, LSL (Locomotive Speed Limiter), DPU systems, PTC, and ECP braking ability (on some units).

Quebec North Shore and Labrador Railway The Quebec North Shore and Labrador Railway is a private Canadian regional railway that stretches through the wilderness of northeastern Quebec and western Labrador. It connects Labrador City, Labrador, with the port of Sept-Îles, Quebec, on ...

has 19 AC44C6M locomotives. These were rebuilt from former BNSF Dash 9 locomotives.

Fortescue Metals Group Fortescue is a global metal mining company headquartered in Australia. Fortescue focused on iron ore mining under the name of Fortescue Metals Group (FMG) until July 2023. As of 2017, Fortescue is the fourth-largest iron ore producer in the ...

has 28 AC44C6M locomotives. These feature a larger radiator than other AC44C6M rebuilds.

Union Pacific The Union Pacific Railroad is a Class I freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Pacific is the second largest railroad in the United States after BNSF, ...

also announced plans to rebuild 75 of their Dash 9 locomotives into AC locomotives, presumably AC44C6Ms, as part of a large order to rebuild much of their GE locomotive fleet. Union Pacific is a major customer of the similar AC4400CWM rebuild program. All of these locomotives are classified as C44ACM, which is similar to the C60AC (including convertibles) and C44AC rebuilds. All of the rebuilds use UP's new paint scheme that was introduced in late 2022. A

Canadian National The Canadian National Railway Company () is a Canadian Class I freight railway headquartered in Montreal, Quebec, which serves Canada and the Midwestern and Southern United States. CN is Canada's largest railway, in terms of both revenue an ...

AC44C6M rebuild was spotted outside of a Wabtec facility in early September 2022. This was later revealed to be an order for 50. 60 more units were ordered in 2023 for a total of 110. In 2025, 11 more units were ordered, raising the total to 121.

Similar rebuilds

The AC4400CWM is a similar rebuild program undertaken by GE/Wabtec, but starts with an AC4400CW or AC6000CW (UP only) instead of a Dash 9. Union Pacific,

CSX CSX Transportation , known colloquially as simply CSX, is a Railroad classes, Class I freight railroad company operating in the Eastern United States and the Canadian provinces of Ontario and Quebec. Operating about 21,000 route miles () of trac ...

, and

CPKC Canadian Pacific Kansas City Limited, doing business as CPKC (known as Canadian Pacific Railway Limited until 2023), is a Canadian railway holding company. Through its primary operating railroad subsidiaries, Canadian Pacific Railway (CP) and ...

have rebuilt several hundred AC4400CW into AC4400CWM models. The AC44C4M is a rebuild similar to the AC44C6M, but AC44C4M locomotives feature 4 traction motors and an A1A-A1A configuration rather than the AC44C6M's 6-traction motors in a C-C configuration. This is similar to the

ES44C4 The Evolution Series is a line of diesel locomotives built by GE Transportation Systems (now owned by Wabtec), initially designed to meet the U.S. EPA's Tier 2 locomotive emissions standards that took effect in 2005. The line is the direct su ...

and ET44C4 that BNSF also operates. These locomotives also retain their original cabs, with the exception of unit 616 as of 2025. BNSF has so far been the only customer of the AC44C4M, with 21 locomotives. They are numbered 599-615 and 617-619 and were formerly

ATSF The Atchison, Topeka and Santa Fe Railway , often referred to as the Santa Fe or AT&SF, was one of the largest Class 1 railroads in the United States between 1859 and 1996. The Santa Fe was a pioneer in intermodal freight transport; at variou ...

C44-9W units.

History

Similar rebuilds

Operators

References

Further reading