Common problem areas are in the point rails and frogs of the railway. Ron Marsh starts with addressing the issues that arise over time in a turnout switch. One problem that often arises with switches in our layouts is picking a switch. This is when the point rails are thrown in one direction but a car and its wheel catches the inside of the point rail causing a derailment.
One cause of this issue is from the build up of dirt, ballast, or other debris over time. You can solve this issue by taking a pointed tool or toothpick and going through the narrow spaces between the point rails and stock rails to clean the debris. Another issue that can cause cars to pick a switch is if you are using switch motors. Sometimes switch motors can put too much pressure on the point rails causing them to bend which can catch flanges on some wheel sets. You can fix this issue by having an NMRA gauge on hand that will tell you everything about the standards of a turnout switch.
The frog being another common area for issues. Where your rails meet at the insulfrog, wide wheels on cars can get stuck over both of the rails that touch. Putting a thick paint or nail polish coat on one rail can help so that wide wheels do not get stuck when passing the frog. A new turnout switch can even cause issues before it is in the layout. Again, use your NMRA gauge to check the size of the railway and make sure it isn’t too tight. If the railway is too tight, you can quickly expand it. Cutting vertically down through the spike head detail and using your gauge to widen the railway can be an easy fix for this issue.
Ultimately, making sure the moving parts are clean and in gauge, you will have a much better time with your turnout switches.