Since I use code 40 rail, I noticed that, especially over turnouts, the trucks were bouncing around a lot. I took the trucks apart and measured the wheels against an NMRA gauge. I discovered that the wheels were a bit too tight. A couple of twists and pulls on the wheels did the trick.



Even after improving the engine's pickup (see my other article), the engine still stalled and humped over the turnouts. I realized that the wheels may be good enough for code 55 track, but their flanges are a bit too tall for code 40. I filed them down and then thoroughly polished the wheel thread surface. You can see the difference in the photo below. I believe Life-Like may have blackened the wheels and some of that got on the wheel thread. When I tested the engine again, it ran flawlessly over my turnouts and didn't stall (no change to the track - no cleaning).