And the two remaining diesel builders are locked in a battle to become the locomotive supplier for the 21st century. Caterpillar owned EMD, no longer a division of General Motors, is represented by the AC-traction-motored SD70ACe and its DC-traction sibling, the SD70M-2. General Electric’s standard bearers are the GEVOs, the Evolution Series ES44AC and ES44DC. GE claims the GEVOs are “the most fuel-efficient, most environmentally friendly diesel locomotives in history… If every freight train in North America were pulled by an Evolution Series Locomotive, the reduction of smog-producing pollutants would be like removing 48 million cars from the road each year.” Everything about these locomotives has been examined, questioned, and re-thought, generating 25 new U.S. patents in the process.

Before they went on sale in 2005, 52 preproduction units were tested in revenue service across the continent for more than a year. Every Big Six railroad has ponied up to buy the ES44, with the BNSF currently rostering the largest GEVO fleet. Around the world, over 3,700 Evolution Series diesels are operating in 10 countries.

Like all M.T.H. locomotives, the new ES44AC offers HO scale’s finest combination of detail, realism, and performance. Listen to the chant of an authentic GEVO-12 motor in the Proto-Sound 3 versions, and throttle down as low as three scale miles per hour so you can admire the details as the Evolution Series glides by: see-through fans and grilles, walkways with safety tread, flashing ditch lights, windshield wipers, body and truck air brake piping, and a host of other separately applied details. Activate the couplers from anywhere on the layout using any DCC controller or the DCS Digital Command System. For the ultimate in power and sound, operate these diesels in multiple-unit lashups under DCC or DCS digital command control. If you’re running under the M.T.H. DCS system, you can doubleor even triple-head the ES44AC with virtually any combination of 3.0 locomotives.

Did You Know? A fully loaded, an Evolution Series diesel carries 5000 gallons of diesel fuel, 450 gallons of lube oil, and 400 gallons of cooling water.

In May of 2007 at its Ecomagination event in Los Angeles, General Electric revealed a prototype hybrid locomotive. The modified GEVO Hybrid works by using  a bank of batteries to capture and store energy dissipated during dynamic braking. This stored energy can then be used to help the locomotive when it is starting to move. This was projected to cut fuel consumption and emissions by up to 10% compared to the standard GEVO's.

As of 2013, this locomotive model has not been brought to market, so this unit remains a very unique and distinctive one. In addition to the unique paint scheme, the model, just like the prototype will have lights along the sill the run in a chasing pattern.

Below is a demo video of the previously released O Scale version:

• Intricately detailed ABS body
  
• Diecast metal chassis
  
• Metal handrails and horn
  
• Metal body side grilles
  
• Detachable snow plow
  
• (2) engineer cab figures
  
• Authentic paint schemes
  
• RP-25 metal wheels and metal axles
  
• (2) Operating Kadee compatible Remote Controlled Proto-Couplers installed & (2) #158 Scale Kadee whisker couplers inluded in box
  • Pick up or drop off a cut of cars or an entire train anywhere on your layout by opening the front or rear coupler remotely, using a DCC or DCS controller
• Prototypical Rule 17 lighting
  
• Directionally controlled constant voltage LED headlights
  
• Lighted cab interior
  
• Illuminated number boards
  
• Operating ditch lights
  
• Powerful 5-Pole precision flywheel equipped skew-wound balanced motor
  
• Locomotive speed control in scale MPH increments
  DCS/DCC versions include nnboard 28 function DCC receiver w ProtoSound 3 with the Digital Command System featuring Freight Yard Proto-Effects
  
• DCC Ready versions include onboard NMRA Compliant 8-Pin DCC decoder plug
• DCS/DCC 3E versions are three rail versions of the model limited to use on HO Scale 3 Rail layouts like Marklin
  
• Operates On Code 70, 83 and 100 track
  
• 1:87 scale proportions
  
• Unit measures: 10 9/16” x 1 7/16” x 2 3/16”
  
• Operates On 18” radius curves