This paper presents methods to compensate and monitor the disturbance generated by electric traction units, considering their position in different times, in a railway system. For this purpose, first of all, experimental data of Italy traction system is used and its components are modeled. Then, using proposed algorithm a suitable location for a passive filter is determined. Subsequently, considering Speed of traction units, the location of each traction unit is predicted and with proposed THD index, created disturbance in each time is determined. Finally, in the span of 1 minute, proposed index is monitored. It is worth mentioning that the Matlab/Simulink software is used to simulate proposed model.