BNSF's C4 ES44's run through?

Are their any interchange restrictions placed on the C4 versions (four traction motor, six axle) of BNSF ES44 units or are they allowed full run-through service?

I would guess there has to be something different with these units. Is there any specific training crews need that might restrict them from run-thru service?

T2

The only thing I can think of that is significantly different about these units as far as operation is the weight transfer system on the center (unpowered) axle but, IINM, it is usually set up to operate automaticaly as part of the unit's traction control system.
Other than that I would think the controls would be like any other Evolution series locomotive...