We introduce in this paper a multi-user terminal system for a container port to reduce the cargo handling cost. Due to the complexity in that system, an efficient yard operation must be desired. Then we propose a dynamic yard operation with trailers in the terminal. By the dynamic operation, the number of trailers can be reduced by 10% while keeping the cycle time of a quay crane the same as one with a conventional operation. Further the average handling time per ship can be 2 hours less with the same number of trailers as in the conventional one.