CPKC and CN, which together transport millions of tons of freight across the U.S.-Canada border, have already begun halting shipments of hazardous materials and refrigerated goods. On Saturday, CPKC announced plans to cease all shipments originating in the U.S. destined for Canada starting Tuesday. Meanwhile, The Canadian Press reported that CN on Friday barred container imports from its U.S. partner railroads, highlighting the gravity of the situation as both companies brace for a possible work stoppage beginning Thursday if no agreements are reached.