The Devils advocate!
Well Well, all my turnouts are Atlas (mostly Customline #6) and a few #4's.
Derailments, yes a few picked points but the problem most always turned out to be wheels out of gauge. But to be honest there is one #6 that is a piece of crap, had to take it out as the points would never close properly when activated with a switch machine. Sitting on a table by it self, yep it would work ever time but add a piece of track in front of the points yup fail every time. Some day when I have nothing to do, and if I'm still alive I'll find out what's wrong with it.
I spent more time on this problem yesterday and found that 1/2 of my old cars have couplers that have to much spring force to latch them. So when the the car is coupled to another one, it tends to turn the truck. Then when it enters the switch it wants to turn instead of going straight. I guess I will go buy a couple new cars and go from there.