求指导

daiyingda

WARNING: Vehicle velocity calculation at Rail-Wheel Pair
         $S_BOGIE_B.$S_WHEELSET_B.$RWP_Left:
         No active contact patch found. Using nominal wheel/roller radius for rot.
         velocity calculation. Ensure that each Rail-Wheel Pair has exactly one
         contact patch, for example by calculating Preloads.

这种问题怎样解决啊