In this study, the inverter noise propagation on rolling stock under dynamic conditions was investigated using a multi-channel time-domain measurement system. Measurement results revealed a dependence on train speed of the noise that propagates between car body and rails that was not found in the inverter common-mode current. Since this difference is presumably caused by the bogie bearings, a special measurement of bogie bearings under dynamic conditions was conducted using roller rigs and a 2-port vector network analyzer. The results clarified the dependence of the electromagnetic noise on speed that was observed during measurements with the train in operation. We then prepared an equivalent circuit on the basis of the measurement results.