California bound: Los Angeles, Long Beach ports regain lost ground.

Shippers are a fickle lot. When port and rail congestion crippled the ports of Los Angeles and Long Beach in 2004, importers immediately diverted large blocks of cargo to the Pacific Northwest and East Coast, and ports there registered spectacular gains that continued through last year.

But while shippers last year were rerouting their discretionary cargo to other ports, terminal operators in Los Angeles-Long Beach were hiring additional labor and keeping truck gates open longer, and western railroads were expanding their capacity. As a result, the 2005 peak shipping season in Southern California was virtually trouble-free.

The same importers who abandoned Los Angeles-Long Beach last year are now returning to Southern California. Several factors are at work. The ports and railroads remain fluid. All-water services to the East Coast are booked solid, leaving the West Coast the only feasible gateway for added cargo volume. Finally, with larger vessels entering the Pacific Southwest services each month, freight rates to Los Angeles-Long Beach have dropped 10 to 15 percent.

"Discretionary cargo is moving back to Southern California," said Paul Bingham, a principal at the research and consulting firm Global Insight. "The region's natural advantages will come back into play."

According to figures published by the Pacific Maritime Association, container …