Evolution Series locomotives are equipped with either AC or DC traction motors, depending on the customer's preference.

Currently, six different Evolution Series models (seven including rebuilds), have been produced for the North American market.

[6] The ES44DC (Evolution Series, 4,400 hp, DC traction) replaced the Dash 9-44CW model in the General Electric catalogue.

The ES44AC (Evolution Series, 4,400 hp, AC traction) replaced the AC4400CW model in the General Electric catalogue.

BNSF Railway is the launch customer for this model, ordering an initial batch of 25 units numbered 6600–6624.

On 30 January 2014 Florida East Coast Railway announced that they would buy 24 ES44C4s, to be numbered 800–823, for heavy haul service and intermodal traffic.

All were delivered by the end of 2014, in order to beat the EPA's deadline on exhaust-emissions standards for new-built Tier 3 locomotives.

One of the differences between an ES44AC and an ES44C4 is the air cylinders and linkages on the truck sideframes of the ES44C4; these are part of the traction control system.

Every time a variation in grade, traction, or wheel slip occurs, the computer adjusts the pressure in these cylinders to maintain sufficient adhesion, by varying the weight on the drive axles.

[8][9] The ES44DCi (Evolution Series, 4400 horsepower, DC traction, international version) was built for the Rio Tinto railway in Australia.

BNSF also ordered similar ET44C4 locomotives, which have a dynamic weight management system instead of a traction motor on the middle axle of each truck.

[12] CSX Transportation ordered 15 of these locomotives, with most being built at their Huntington Heavy Repair Shop.

The most noticeable difference is the radiator section at the rear of the locomotive is larger to accommodate the GEVO's air-to-air intercoolers.

The increase in radiator size is due to the necessity for greater cooling capacity in the locomotive in order to reduce emissions.

The other major difference between the Evolution Series and earlier models is the vents below the radiators, which are larger than those on previous GE locomotives.

It is painted in a Chicago, Rock Island and Pacific Railroad heritage scheme in honor of this Iowa Interstate predecessor.

[2] Transnet Engineering in South Africa has a license to manufacture 233 4,200 hp (3,100 kW) 3 ft 6 in (1,067 mm) Cape gauge ES40ACi locomotives for Transnet Freight Rail, with core components including GEVO-12 engines supplied from the United States.

In October 2015, the first of the 227 South African-built locomotives was nearing completion at Transnet Engineering's Koedoespoort shops in Pretoria.