The ES44C4 is exclusive to the BNSF. No other railroad currently owns this model.

The BNSF developed this model in hopes of reducing maintenance costs while still providing the tractive effort (pulling power) of their C44-9W models. It has been extensively tested on every track profile the BNSF operates hauling nearly every commodity except coal.

Typical "Dash 9" locomotives operate with six traction motors, one powering each axle. The "C4s" utilize only 4 traction motors, one on the forward and rearward axle of each truck thus leaving the center axle non-powered. As the amperage or "load" increases from the generator, the center axle is raised ever so slightly, as to increase the weight on the powered axles, to achieve the desired pulling capacity. This is accomplished by using pistons similar to brake cylinders, attached to linkage that actually lifts the center axle. From what I have observed, it must be working as the BNSF now has over 400 units of this model in service.

This video provides a glimpse underneath the trucks to show the void where a traction motor would normally be placed on the center axle. Hope I'm not boring anyone - lol. Footage taken 10/29/2012.

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