Reply to "Mth realtrax switch sparking"

I have some rolling stock that also do this on RealTrax switches.  Mostly postwar stuff made before angled wheels.  I do have one lighted Williams caboose that also does this. It happens so infrequently that I wasn't too concerned about it, but it looks like the gap on the plastic guide to keep the wheels on the right path can be culprit. Some have closed that gap by adhering a thin plastic strip to narrow that gap.