The Port of Tacoma, in Tacoma, Washington, is the largest container port in the Pacific Northwest and the fifth largest in the United States, handling 1.74 million 20-foot equivalent units (TEUs) each year. Despite its size, the Port's future depends on adequate preparation for a nearly 100% increase in cargo by 2008. Growth in Pacific Rim trade is expected to double containerized freight through Tacoma in five years, which would also impact the Port's rail infrastructure since the most important containers are loaded on double-stack trains and dispatched to Midwest and East Coast markets. In 2003, Port officials began an expansive rail study in order to determine how much more staging track would be needed, and where and when to build them. Their goal was to build a new, expanded terminal complex, complete with a new way to connect to the existing rail network. They also wanted to alleviate any customer concerns about meeting future capacity requirements.

While the new terminal was expected to support even the needs of the Port's biggest client, Evergreen Marine of Taiwan, for the next 20 years, the Port still needed to verify the design. The Port engaged Automation Associates, Inc. (AAI) to build a simulation model incorporating both port and rail activity. This model would be incorporated into their rail study and would help prove the operational feasibility of the new terminal. Given that the existing rail network serviced nine other terminals and supporting staging yards, the Port needed to display the impact of the new terminal. The Port had to answer questions such as:

• Is sufficient staging yard capacity available, and should different staging yards be used to support each terminal?
• Would the configuration of the network introduce unforeseen issues with the level of service the Port's customer have relied on for years?
• What traffic flow bottlenecks will exist, and what operational or design changes would be effective in mitigating them?

Over the last 15 years, AAI has provided simulation modeling and analysis for major U.S. ports, including the Port of Los Angeles and Port of Long Beach. They combined insight from these experiences with their Transportation Modeling Studio (TMS) framework to develop a model that represented the Port of Tacoma's unique operations, current and planned rail network layouts, and plans for growth. Working together with the Port and their primary rail operator, Tacoma Rail, the AAI team developed a detailed simulation of the movements of trains in and out of the terminal complex. The model tracked the precise time each train arrived and left, providing advance warning of possible congestion points in the rail network. The model also logged the movements of containers through the complex, carefully noting traffic flow, and indicating where staging yards and terminals may reach their capacity limits.

"The Port of Tacoma used TMS to prove various design cases and rule out certain scenarios," says Randy Gibson, president of AAI. "The model helped the Port understand how the new design would affect operations for all terminals, and gave officials a view of how network congestion and traffic schedules would be managed with the rise in cargo growth."

Employing the simulation model's robust "what-if" capabilities, Port officials added hypothetical trains and ship calls to visualize how the new complex would tolerate increased cargo volume. The users added and removed train tracks and changed arriving and departing train schedules to identify potential network congestion points. Port users also tested to see which staging yards should be used to support each terminal. They also ran simulations to determine whether the configuration of the network would have unforeseen consequences that might affect the Port customers expected level of service.

The simulation model proved that the Port's proposed size, location and operations of the new terminal were sufficient to handle the expected volume for Evergreen Maritime and other clients. In the fall of 2004, Evergreen brought five of the world's largest shipping cranes to the new 171-acre facility. In January the shipping giant officially took possession of the $210 million terminal.

The return on investment was immediate for the Port of Tacoma. By retaining its largest client, the Port was able to increase its throughput, resulting in millions of dollars in additional revenue. “We were able to take the work that AAI had done, and continue to perform our own analyses successfully,” said Rob Collins, the Port’s Director of Intermodal Services. “Our clients were convinced of our ability to operate the new Evergreen terminal. We attribute this success to AAI’s skills in developing an easy to use and maintain tool that directly met our business needs.”

The Port of Tacoma will continue to use TMS to plan future expansions in rail capacity serving the complex and expansion of the Evergreen facility itself. The new terminal is configured to grow 237 acres, including a 108-rail car intermodal yard, which will make it the largest single West Coast terminal north of Los Angeles.