Abstract. There are many reasons, why electric drive systems will be used in future more frequently in transportation systems. The electrification allows a flexible use of different energy sources and thus creates a greater independence from fossil energy. However, electric drive systems are a challenge for the manufacturers of transportation systems. The electrical powertrain can not only be exposed to interferences, it may also emit interferences into components and communication cables in the vicinity. This can be a high risk for the drive system and for the passengers. For that reason, an EMC study of an electrical powertrain for transportation systems is presented. There the interference at the unshielded high-voltage cable (HV-cable) is characterized. The analysis of the influence of position variation of the communication cable with respect to the unshielded HV-cables is one main aspect. Different optimizations have been added to the test setup.