The railway industry is facing a digital revolution with several wireless technologies disputing the electric transportation market. These candidate technologies have the challenge of ensuring continuity of service despite the presence of transient electromagnetic interference from the pantographcatenary interface. In this context, we propose a procedure to design test waveforms that faithfully represents this physical phenomenon and, at the same time, can be easily generated in the laboratory to evaluate the susceptibility of railway communication systems. Experimental results involving the wireless technology LoRaWAN suggest that the transient sequence length can play a role in communication reliability.