Railworks America

Hello guys.
Look in image why this unknown shadow is appearing in game ?

This shadow is visible if i will add more than 2 objects (Brown color object at left side)

Thanks please help me fast

The picture shown is in the world editor. Does the shadow appear when you actually go into game here?

Yes (Its show also in game)
actually i created this object simple box. without any shadow object. when i will place upto 3 then this shadow will appear.