Work on the Middle Harbour Redevelopment Project will be done in phases, according to James Hankla, president of the board of commissioners.
Construction could begin as early as December.
"This is a chance to move these two terminals into the modern era, into the container shipping industry's greener and more business-friendly future," Hankla said.
The project aims to improve the port's competitive position and implement measures to head off threatened lawsuits to force reductions in port-related pollution.
About 65,000 feet of railroad track will be added so that nearly one-third of Middle Harbour's cargo will be moved by train and, with dockside electrical power to become available, vessels will be able to turn off their auxiliary diesel engines.