The contingency plans by the ports come as some ocean carriers are cutting off new export bookings ahead of the possible work stoppage and issuing surcharges for cargo en route to ports that may be closed on Oct. 1.
Higher-than-expected retail sales in stores and online last month helped increase truckload shipments, but excess capacity is keeping rates in a holding pattern.
The port, at the confluence of the Rhine and Rhur rivers, is in the industrial heartland of Germany and a key transshipment point for intermodal cargo in Northern Europe.