Editing GE Evolution Series (section)

=== ES44C4 (2009–2020) ===
[[File:BNSF 8013.jpg|thumb|[[BNSF Railway|BNSF]] ES44C4 No. 8013]]The '''ES44C4''' (Evolution Series, 4,400&nbsp;hp, C to denote 3 axles per truck, 4 traction motors) was introduced in 2009. While similar to the ES44AC, the ES44C4 has two traction motors per truck, instead of the conventional three such as on the ES44AC. No ES44C4s with DC traction were built.  The center axle of each truck is unpowered, giving an A1A-A1A wheel arrangement. BNSF Railway is the launch customer for this model, ordering an initial batch of 25 units numbered 6600–6624.<ref>{{cite news|url=http://www.railwaygazette.com/news/single-view/view/ge-unveils-es44c4-locomotive.html|title=GE unveils ES44C4 locomotive|publisher=[[Railway Gazette International]]|date=27 May 2009|access-date=25 January 2012|archive-date=12 October 2012|archive-url=https://web.archive.org/web/20121012100714/http://www.railwaygazette.com/news/single-view/view/ge-unveils-es44c4-locomotive.html|url-status=live}}</ref> The ES44C4 was initially only built for BNSF. The 4200s and units 7921-7999 are certified as Tier 4 Credit units, while the others are Tier 2 or Tier 3. 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.

A feature of these units is a variable traction control system in their computer systems. 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.<ref>{{cite web|url=http://www.railwayage.com/content/view/855/121/|title=GE Transportation unveils new Evolution Series locomotive|access-date=3 November 2009|archive-date=27 September 2011|archive-url=https://web.archive.org/web/20110927134033/http://www.railwayage.com/content/view/855/121/|url-status=dead}}</ref><ref>{{cite web |url=http://www.gevirtualrailexpo.com/ge_virtual_rail_expo/media/files/model-es44c4.pdf?ext=.pdf |title=Archived copy |website=www.gevirtualrailexpo.com |access-date=11 January 2022 |archive-url=https://web.archive.org/web/20141031161946/http://www.gevirtualrailexpo.com/ge_virtual_rail_expo/media/files/model-es44c4.pdf?ext=.pdf |archive-date=31 October 2014 |url-status=dead}}</ref>