The country’s two main freight railways are ramping up the amount of cargo being turned away ahead of a potential lockout next week that could snarl supply chains and disrupt industries.

Canadian National Railway Co. schedules show that, starting today, it is barring container imports that originate at ports ranging from New York City to Mexico.

CN and Canadian Pacific Kansas City Ltd. are also beginning to halt shipments that need cooler temperatures, such as meat and medicine, to avoid seeing stranded loads go bad should a work stoppage occur.

The two railways have warned that 9,300 engineers, conductors and yard workers will be locked out on Thursday unless they can reach new collective agreements, while the union has also said it is poised for a strike.

Both sides remain at the bargaining table after weeks of deadlock over scheduling and wages, with shipments of chlorine for drinking water already halted as part of a phased shutdown poised to progress even further next week.

Yesterday, federal Labour Minister Steven MacKinnon rejected a request from CN to impose binding arbitration as the negotiating clock ticks down.