If East and Gulf Coast ports are forced to shut down, the U.S. could see inventory shortages, higher costs at grocery stores, and months-long container backlogs.
The Railway Association of Canada says that more than half of the country's exports are moved by rail, in addition to 70% of its intercity surface freight.
Ahead of looming deadlines, it's unclear whether either situation will resolve in time to avert these twin crises, or how long any potential work stoppages might last.