The design of the pilot truck is the chief flaw, in terms of tracking at least. The mount is a screw in the center of the truck, which passes through a round hole. This forces the truck to rotate on an axis. In a turnout, or other typical sharp N scale turn, this means that the rear wheel of the truck will want to kick off the rail, since the screw acts like a fulcrom to the front wheel's lever. I'm going to see if there's a way to "oval" the hole for the screw to allow a little more slop side to side.
That should help the truck guide the locomotive into a curve, rather than buck it the whole time.
Lee
