With increasing train speeds the subsequent increase in slipstream velocities can have a detrimental
effect on the safety of persons in close proximity to the vehicle. Due to their uneven loading and bluff
geometries, freight trains can produce higher slipstream velocities than passenger trains at given
measurement locations. The highly turbulent non-stationary slipstream of a model-scale Class 66
locomotive and wagons was investigated using delayed detached-eddy simulation (DDES). The Reynolds
number of the flow was 300,000 and results were compared for meshes of 25 and 34 million hexahedral
cells. Good agreement was observed between the DDES and model-scale physical experiments.
Slipstream velocities along the train side and roof were investigated and the bogie region was seen to
produce the highest slipstream velocities. A comparison between time-averaged and ensemble-averaged
data from the simulations gave comparable results. The technical standards for interoperability (TSI)
analysis showed that the slipstream velocities generated were below half of the maximum permissible
value of the standard whereas the pressure was 43% greater than the limiting value. Furthermore the
presence of a periodic phenomenon is detected above the roof of the locomotive