When the container transportation system was developed in the last century, it was built on linear ship berthing and a crane loading and unloading the ship on one side only. The crane was equipped with a boom that could reach across the entire width of the ship. Container pick-up, transfer and drop-down was done by a trolley that travelled along the boom and a fixed bridge girder, usually equipped with a backreach.
Space was needed on the ground for vehicles to receive and transport containers to the container stacking yard, and vice versa. The crane could travel along the quay on rails to position itself as needed with each line of containers on the ship deck or below, and/or to move from one ship to another. While travelling, if the crane encountered obstacles in the ship superstructure, the boom could be raised to a semi-vertical position. The trolley itself could be equipped…
