Transportation of steel, copper, aluminum and zinc between the United States and Canada is at risk of a strike by Canadian National Railway Co.

Union Pacific Corp., the largest freight rail supplier in the U.S. western region, said this week that it will stop accepting incoming and outgoing goods from the Canadian branch of CN railway until Canadian rail operations return to normal.

A report by Credit Suisse Group AG said zinc and copper from Toronto based hudby minerals Inc.'s operations in Manitoba would be negatively affected by a long strike. Hudbay did not immediately comment.

Anton Posner, chief executive of supply chain management and consulting firm mercury resources, said in an interview that a notice to customers from the Union Pacific could damage copper and steel shipped from the US. Delivery of aluminium from Quebec to the US could be delayed, he said.

"It should have an impact, but we're not sure how much," Posner said by phone on Thursday. "It's a bit like you're trying to take off from Houston, the pilot is sitting on the tarmac, and you're on the ground because LaGuardia's airport is so crowded."

About 3200 Canadian railway workers went on strike Tuesday, citing problems such as working conditions and medical benefits, according to the Teamsters Canada rail conference Union. The company's share price fell for the fourth consecutive day, falling 3.2% this week.

Cn railway's annual report shows that it serves all nine smelters in Canada. The company also said it has a network of 16 strategically located metal distribution centers, as well as the country's largest metal transport fleet.

In its 2018 annual report, Teck Resources Ltd. said that Canadian National Railway serves its operations on the Alberta cardinal River, which ships its products to ports on the west coast. According to the company's website, the Vancouver based company mines steel-making coal in the cardina river.

"We have been closely monitoring the situation, assessing potential impacts and implementing mitigation measures," said Chris stannell, a spokesman for tech, in an email statement. Any disruption of rail services is detrimental to Canada's overall economy. This has a negative impact on the shipper's business and international reputation. "

Alan Kestenbaum, chairman of Stelco Holdings Inc., based in Hamilton, Ontario, said the strike did not affect his company.

"We have our own rail cars and a variety of options, including the use of barges, ships, trucks and alternative rail lines," he said in a text message

"Shipments from the smelters we operate are not affected at the moment, but we are paying close attention," said Jim Beck, a spokesman for Alcoa. "The largest aluminum producer in the United States operates smelters in Baie Comeau, becancourt and deschambault in Canada. （From CCMN)