Here's the Wiki version http://en.wikipedia.org/wiki/GE_AC6000CW Looks like CSX and UP here in the States and BHP in Oz with considerable problems that are being remedied slowly.
BHPBIO's units have been retrofitted with GEVO-16's and are performing well, same as when they arrived. BHPBIO spent the time fixing them unlike other roads.
CSX also have there AC6000 remotor with GEVO-16, UP been remotoring theres with 7FDL-16 engines to make them like there AC6044. CSX has the biggest fleet at 115.