Today I wired up about half of my HCD layout, and started testing my trackwork only to discover that one rail was sitting a little high, causing the pilot truck to derail. I cleaned up the bump, and derailment continued. I then realized that the pilot truck was hitting the MTL 905 that I installed. I would up cutting off the back of the coupler box, and everything is working fine.
My daughter’s Micro-trains SW1500 ran over the bump without any issues. My SW on the other hand sounds like a coffee grinder, and I am sure has something bent. I took the loco all the way apart and could not find the cause.