The panamax is the draft limits of the Panama Canal, which imposed a ship's carrying capacity limit to around 3,500 TEUs (twenty-foot equivalent units). Modern container ships exceed the panamax, that is, cannot transit the canal. The future container ships in the deep-sea voyage are expected to be much bigger than those currently in service. The landbridge service that utilizes the West Coast ports in North America becomes more important in the Trans-Pacific Route.
There were plans to build a dry canal---rail line for container traffic---linking the Pacific Ocean and the Caribbean Sea in Central American country (e.g. Nicaragua) using the landbridge service, in order to meet the increasing flow of cargo between the East Asia and the North and Latin America.