1. A CONVEYOR SYSTEM COMPRISING A VEHICLE TRACKWAY, A GUIDEWAY DISPOSED BENEATH SAID TRACKWAY, A DRIVING STRIP HAVING NOTCHES AT ONE EDGE AND ARRANGED IN SAID GUIDEWAY WITH ITS NOTCHED EDGE PROJECTING INTO THE CONFINES OF SAID TRACKWAY, AND A PLURALITY OF CARRIERS DISPLACEABLE ALONG SAID TRACKWAY, EACH OF SAID CARRIERS COMPRISING A BODY PORTION, A CATCH DEVICE PIVOTALLY ASSOCIATED WITH SAID BODY PORTION, AND HAVING A CATCH PIECE FOR RELEASABLE ENGAGEMENT WITH THE NOTCHES ON SAID DRIVING STRIP, A LOAD-SUPPORTING MEANS CONNECTED TO SAID BODY PORTION AND DISPOSED TO APPLY A LATERAL TILTING ACTION TO SAID BODY PORTION IN RESPONSE TO LOADING THEREOF, AND A BIASING MEANS CONNECTED TO SAID CATCH PIECE FOR BIASING SAID CATCH PIECE INTO ENGAGEMENT WITH A NOTCH ON SAID DRIVING STRIP IN RESPONSE TO THE AFORESAID LATERAL TILTING ACTION.