Abstract:With the rapid development of high-speed railway, turnout faults have been an urgent problem to be solved. Firstly, from the operation principle of turnout, the influence of traction force of switch machine on turnout is studied; then compared to the power and current parameters of the switch motor, and it was found that the switch traction can more directly reflect the operation conditions of turnouts; finally it put forward the turnout fault diagnosis algorithm based on PSO-SVM and the switch traction parameters. After the processing of the actual data, it was found that this diagnostic method had good resolving power on the turnout faults.