It could be a number of things. Sometimes turnouts have poorly made frogs. They may not be deep enough or may not be aligned properly. An NMRA track gauge can help with incorrect frog geometry and also improperly gauged truck wheels.
Sometimes guard rails need to be filed down, too, if they are too high.
Track work needs to be smooth and free of kinks. Poorly laid track causes most derailments.
It takes an iron man to play with a toy iron horse.
Hi all long time no see,I have 4 Atlas HO switch tracks I have had for along time.I had to remove the.Switch tracks due to derailing problems I had taken.A Ho freight car truck and put my finger on top.Of the truck and when I ran the truck of the plastic part.Where the switch is,It stops and gets stuck has anyone had these issues? What can I do to fix this issues hope you can help.