1. Mechanical failure of turnout, such as too tight adjustment of turnout, foreign objects in turnout, obstacles during turnout conversion, etc. , resulting in switch conversion is not in place or poor adhesion.
2. Switch circuit fault, such as indicating the change of pole gap, the inspection column can't fall into the pole gap, the contact of the switch machine is poor, the indicating circuit is open or the terminal contact is poor, and the rectifier diode is damaged. , resulting in the turnout can not give the correct indication signal.
3. Turnout control failure, such as the single control button stuck, the proximity lock failed, the interlock condition was not met, the turnout section was occupied by a car or the track circuit failed, which caused the turnout to be unable to operate or switch.