A loading and unloading system for containers at quayside comprising: a) a two levels quayside transit structure on shore to hold containers for either loading or unloading for a container ship at an indented berth or a conventional linear berth; b) a container crane with a middle section and two side sections, wherein the middle section is supported on vertical columns, allowing any elevated height for ship clearance, having a pair of lifting means each connected to a spreader for the container crane for lifting containers from the container ship, a plurality of motors and cables and a plurality of braking means, allowing the upward and downward movement of the spreaders, wherein the container crane is capable of lifting containers to or from said transit structure; and able to load and unload to both sides of the indented berth to and from the two levels of the transit structure simultaneously by one single crane and within one cranespace; c) rails mounted horizontally to the middle and side sections of the container crane such that the lifting means is slidingly moveable horizontally along the rails of the middle and side sections of the crane to operate the lifting of containers above the container ship to the two different levels of said transit structure on quayside; and d) a plurality of leg supports structurally mounted at both sides of the indented quayside to the ground or a supporting structure to support the container crane, wherein the container crane comprises a total of four pairs of leg supports which is structurally stable, wherein the lifting means is permitted to move along the rails, wherein the crane operates loading and unloading simultaneously to unload containers from the container ship and store the loaded containers at the quayside transit structure, wherein a plurality of loading and unloading systems are being operated simultaneously to increase the efficiency in loading and unloading of containers; characterized in that the middle section of the crane is movably supported on the vertical columns independently of the two side sections so that it can be elevated and lowered when the container ship is berthed and secured for loading and unloading of containers. a) a two levels quayside transit structure on shore to hold containers for either loading or unloading for a container ship at an indented berth or a conventional linear berth; b) a container crane with a middle section and two side sections, wherein the middle section is supported on vertical columns, allowing any elevated height for ship clearance, having a pair of lifting means each connected to a spreader for the container crane for lifting containers from the container ship, a plurality of motors and cables and a plurality of braking means, allowing the upward and downward movement of the spreaders, wherein the container crane is capable of lifting containers to or from said transit structure; and able to load and unload to both sides of the indented berth to and from the two levels of the transit structure simultaneously by one single crane and within one cranespace; c) rails mounted horizontally to the middle and side sections of the container crane such that the lifting means is slidingly moveable horizontally along the rails of the middle and side sections of the crane to operate the lifting of containers above the container ship to the two different levels of said transit structure on quayside; and d) a plurality of leg supports structurally mounted at both sides of the indented quayside to the ground or a supporting structure to support the container crane, wherein the container crane comprises a total of four pairs of leg supports which is structurally stable, wherein the lifting means is permitted to move along the rails, wherein the crane operates loading and unloading simultaneously to unload containers from the container ship and store the loaded containers at the quayside transit structure, wherein a plurality of loading and unloading systems are being operated simultaneously to increase the efficiency in loading and unloading of containers; characterized in that