Modern trains with active line-side converters are currently the state-of-the-art technology in the traction industry. In such systems, the active line-side converter of the drive system can be exploited for power quality improvement purposes. In this paper, adopting the active line-side converter, an identification strategy is proposed, which estimates the parameters of the catenary line through the injection of low-order harmonic current and monitoring the corresponding voltage at the connection point of the pantograph to the network.