I have two Katos, a SD90MAC and SD40-2, I run them with the SD90 in the lead. The like good at derailing stuff. they can't go to the inner loop of the two in the original part of my layout. each can go one at a time, but together the SD40-2 gets flipped off the track by the SD90 as it come off the switch (see my layout page on the line below) once I get them past, they derail the first car behind them. I have the MT long couplers on. I was just trying to drive them in to the switching yard and they decoupled the car just going through the switch, and it's not all that tight of a curver there. What is it about Katos that makes them like to derail stuff? I have Altas SD60 that I can drive full out through these same section ok.