 As one of the three major ports on the West Coast of the United States, the Port of Oakland is the largest seaport on San Francisco Bay and the fifth busiest container port in the United States.It was one of the earliest seaports to switch to containerization and to intermodal container transfer, thereby displacing the Port of San Francisco, which never modernized its waterfront.One of the earlier limitations to growth was the inability to transfer containers to rail lines, all cranes historically operating between ocean vessels and trucks.