I try to avoid getting wood shavings into turnout mechanisms (and tracks in general). Today I had to drill some holes for additional wires and I came up with a simple technique for minimizing the mess produced when drilling holes near tracks. I got a sheet of transparent plastic and made a hole in it which I then laid over the layout with the hole in the plastic where I needed to drill. While holding the plastic in place I was able to drill the hole with the other hand.
As you can see, most of the sawdust is kept off the tracks and the small amount below the plastic is limited to the area around the hole.
When done, one can lift the plastic up without spilling the shavings, and the material below the plastic is easily vacuumed up.
Do not try to drill the hole in the plastic, it will likely wrap itself around the drill bit. Cut the hole large enough to leave some room around the drill bit so that the bit does not catch the plastic.