Talks to end a strike by thousands of workers at Canada's biggest railroad, Canadian National Railway Co., continued on Wednesday, as industrial plants slowed output of products cut off from their markets.

About 3,000 unionized workers, including conductors and yardmen, hit picket lines on Tuesday after talks with management failed to resolve contract issues amid softening demand for freight service. Negotiations in Montreal were "ongoing," Teamsters union spokesman Christopher Monette said.

The union's concerns center on fatigue, safety and ensuring that workers' breaks are not reduced.