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Ports believe pool of more than 80,000 interchangeable chassis will help ease West Coast congestion.
Labor Secretary Thomas Perez met both parties accompanied by a mediator from the Federal Mediation and Conciliation Service who has been assisting in the talks since early January.
Maersk Line CEO Soren Skou told American Shipper container lines need to adapt to permanent overcapacity, and cited Maersk's network management as the primary driver of bumper profits in recent years.
Experimental off dock drop yard at the Port of Los Angeles could help speed containers.
The International Association of Classifications Societies said it would continue to study the report and the will finalized the requirements soon.
The federal agency alleges shipments did not include relevant documents and were improperly packaged and labeled.