Abstract: A method for detecting physical interference with desired transport of an article. The method includes the step of detecting an operative acoustic signal representing the structure-borne sound pattern of an article during said article transport, and detecting the presence of interference based on the acoustic signal. A system for performing the method includes a transport device adapted to transport the article through a predetermined path and an acoustic sensor in structure-borne acoustic contact with the transport device and capable of producing an acoustic signal indicative of physical interference.