Thousands of workers at Canada's largest railway went on strike for the first time in a decade on Tuesday, disrupting the shipping of commodities and sparking calls for Prime Minister Justin Trudeau's Liberal government to intervene.

About 3,000 unionized workers, including conductors and yardmen from Canadian National Railway, hit picket lines, after both sides failed to resolve contract issues at a time of softening demand for freight service.

They continued talks on Tuesday in Montreal amid union concerns over fatigue, safety and ensuring workers' breaks aren't reduced.