A deeper Jacksonville port to accommodate larger ships through the Panama Canal

An article in the New York Times (July 27, 2013) describes a move to increase the depth of the Jacksonville port from 40 to 47 inches, through dredging, to accommodate the larger ships that will be passing through the Panama Canal. But the goods brought in then need a rail hub to move them to inland locations. So Jacksonville is also planning to expand their rail terminal to enable efficient flow. Given competition from other ports and rail hubs, how should the return on investment from Jacksonville’s expansion be computed ? How much of the resulting supply chain cost reduction for shippers and retailers should be recovered to finance these infrastructure costs ? Given mature markets in the US for several imported goods, is this a zero sum game across port operators ? Will lower import costs reduce the incentive for US sourcing and thus make domestic manufacturers and US factory workers worse off ?