A CSX ES40DC (though, eventually re-rated to an ES44DC like most earlier GEVO units owned by the railroad) with an AC4400CW coupled. (Notice how the rear radiator "fins" or "wings" looks very different).

General Electric's Evolution Series is a series of fuel-efficient, high-horsepower diesel locomotives first introduced in 2003, with production beginning in 2005. The Evolution Series is GE's current domestic locomotive series, and over 5,000 units have been produced.

The series was initially designed to follow the US Environmental Protection Agency's Tier 2 diesel engine pollution/exhaust regulations; since then GE has built Tier 3 and Tier 4-compliant Evolution engines.

The Evolution Series, was designed to replace GE's Dash 9 and AC4400CW models. The Tier 2 and Tier 3-compiiant runs are externally similar to their predecessors, with the only main difference being a larger radiator section in the rear third of the engine. The radiator includes a GEVO exhaust particle filtering unit fitted in front of the actual radiator vents. In addition, the radiator extends all the way to the rear end of the locomotive.

Tier 4-compliant GEVO's feature much larger radiators with split cooling. Pre-production demonstrator GEVO's also feature a "hump" in the middle of the long hood, which houses a urea-injection exhaust aftertreatment system. No railroad has ordered the urea aftertreatment system, making the "hump" irrelevant on Tier 4 production models. The Tier 4 units have been unofficially named "ET" rather than "ES", the "T" stands for "Tier 4". This designation is currently only used by BNSF.


  • ES44DC - C44-9W successor. See here: GE ES44DC.
  • ES40DC - 4,000 horsepower version custom-built for Norfolk Southern and CSX, all have been re-rated to 4400 horsepower since.
  • ES44AC - AC4400CW successor) See here: GE ES44AC.
  • ES44AH - ES44AC ballasted to 420,000+ lbs for added tractive effort, custom-built for CSX Transportation and Union Pacific.
  • ES44C4 - A1A-A1A trucked version (only 4 powered axles), so far only owned by BNSF Railway and Florida East Coast Railway. See here:  GE ES44C4.
  • ET44AC - Tier 4-compliant version of the ES44AC, to begin production in summer 2015.
  • ET44C4 - Tier 4-compliant version of the ES44C4. First production unit is BNSF 3916, built in May 2015.
  • ES44DCi (see here:
  • ES59ACi (6,000 hp export locomotive sold to China) 
  • ES58ACi(broad-gauge 5800 hp Brazilian version of the ES44AC)
  • ES60AC (CSX conversion of old AC6000CW to 16 cylinder gevo engine)


  • Earlier ES44AC and ES44DC units were often classified as an AC44EV or a C44EV before the term "GEVO" was used; besides the official series name being officially developed.
  • AC45CCTE is the name often used by Union Pacific GEVO units, mainly because of the fact that they have slightly more tractive effort due to management software.
  • BNSF Railway had their earlier ES44DC's painted in their Heritage 2 (H2) paint scheme, and eventually their Heritage 3 (H3) scheme which made them the first to have the Heritage 3 scheme.

    The rear of a BNSF H3-painted ES44DC.

  • Union Pacific 7964 was the 5,000th GEVO ever produced, and wears special banners to commemorate the milestone.
  • The ES58ACi oddly doesn't include a different style of trucks, but rather narrow DC "hi-aid" trucks.
  • Norfolk Southern (NS) has a fleet of ES44AC GEVO units (including a fleet of SD70ACe units as well) painted in special "heritage" schemes as part of their revived "heritage" program in 2012 (aside from the railroad's 20th anniversary and corporation's 30th) to commemorate the railroad's pedecessors and ancestry. Such units or locomotives are known simply as "heritage units".
  • The Lehigh Valley and Norfolk And Southern (the original NS) heritage units both received numerous updates to make their once-slightly inaccurate schemes more accurate.
  • Because of how many railroads became defunct during the same coincedental years, all of NS' heritage units aren't numbered like UP's fleet of SD70ACe heritage units.
  • Iowa Interstate (IAIS) #513; an ES44AC, was also painted in a special scheme to dedicate the CRIP (Rock Island) railroad's heritage, primarily because of how the actual railroad operates mostly over former Rock Island trackage.
  • IAIS #516, another ES44AC, was also painted in a CRIP commemorative scheme, made to resemble the red and yellow scheme, but with "Iowa Interstate" text on the sides of the unit. This has earned the unit the nickname "McGevo" due to its paint looking similar to McDonalds coloring.