Commissioners likely will hear cautious optimism and continued belt tightening during the budget and cargo update at their May 6 meeting. While container volumes remain down over the same time last year, reflecting Maersk’s move last June to Seattle, the Port now forecasts total container cargo for the year to be 8.6 percent higher than originally estimated last fall. Rail volumes, boosted by Union Pacific Railroad’s year-old domestic service, are expected to rise 22.6 percent higher than previously forecasted. Revenue for the first quarter of this year is down 3.8 percent from the original estimate. Offset by lower expenses, net income through March is $1.4 million higher than expected. The meeting agenda also includes contracts for security system design and roof repairs to the Port maintenance building. Commission meetings begin at noon in Room 104 of The Fabulich Center. Meetings also are available for viewing live and on demand from the Port’s Web site — http://www.portoftacoma.com .