Hi,
There is some simple tuning with Kato #4 switches that will remove the vast majority of derailment problems. See my Pbase.com/atsf_arizona album here:
https://pbase.com/atsf_arizona/kato_4_turnout_tuning&page=allThe info:
These photos show simple tuning modification to #4 Kato N scale turnouts, to alleviate common problem where N scale equipment will pick the points on the #4. This simple modification prevents derails and the point picking.
The problem, which has been known for years, is that the end of the #4 turnout's point is not, well, a point, but is cut off square. Also, there is no 'notch' for the points to sit into. So we do two things: 1) file a notch in adjoining stock rail for the points to sit into 2) sharpen the points. It goes very quickly and is very easy to do.
To carve the notch in stock rail, I put the points in the straight position, then use a small thin file and carve a notch in the adjacent stock rail. This provides a place for the points to 'sit' into, and thus provides a smooth path for the wheels/flanges. In the following photos, you can see the smooth path that this simple filing creates.
Some photos:
At the above
https://pbase.com/atsf_arizona/kato_4_turnout_tuning album, I also added some photos from Tudor on Trainboard.com, his photos further illustrate this modification. He's also got a few nice photos about adding electrical feeder wires from underneath.
Check out this Pbase photo album to see all the photos:
https://pbase.com/atsf_arizona/kato_4_turnout_tuningHope this helps!