Abstract: The present invention provides a high productivity, high density container storage yard adjacent to a facility for loading and unloading containers, such as to and from ships, with the individual containers stored therein being stacked up to four containers high. An integrated container handling system is designed to move the containers from the container storage yard to the loading and unloading facility, and includes an overhead grid rail system on which container carrying shuttle vehicles are routed to designated yard locations by a master control system. Passive switching mechanisms are utilized to selectively move the shuttle vehicles through the grid rail network, wherein the actual switch mechanism is carried on the shuttle vehicle rather than on the track. One disclosed embodiment of the loading and unloading facility comprises overhead cranes and associated buffers in a marine terminal for loading and unloading a container ship.