So all was fine until today when I started having a derailment (see pic) with the lead boxcar behind my Legacy SD90MAC (6-82761) when it entered the switch shortly out of a curve. I thought at first it was because the switch is an older unit but all looked ok. Then I tried relocating different box cars as the lead unit and it still derailed, each time to the inside/turnout part of the switch. Hmmm… I had not had this issue two days ago with the very same locomotive and consist. Weird.
So I tried attaching a different/heavier car as lead - an MTH auto transporter. No derailment. So then I began looking at the coupler on the locomotive and found it did not swing freely; it actually felt kind of rough? I tried lubricating the pivot point but it still feels much stiffer than my other units. No idea what/why this changed but it did.
My question is should/can I replace the coupler assembly or would a disassembly and clean up suffice? Has anyone run into this before?
Thanks to all!
