Roughly 3,300 striking engineers and conductors at Canadian Pacific Railway Ltd. are headed back to work, but experts say serial government intervention is making future strikes more likely.

The workers abruptly ended a two-day strike Monday, after CP and the Teamsters union agreed to arbitration, just as the federal government was poised to order them back on the job.

CP rail service across the country, including train service for roughly 19,000 commuters in the Montreal area, is expected to return to normal Tuesday.

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Federal Labour Minister Kellie Leitch hailed the end of the strike, which began Saturday, as "great news" for the Canadian economy.

"The strike is over," Ms. Leitch told reporters in Ottawa. "This will bring an end to the work stoppage that could have seriously harmed the Canadian economy."

But labour relations experts warned that intervention by Ottawa is doing more harm than good because research shows intervention makes future strikes much more likely.

"It chills bargaining," explained Robert Paul Hebdon, an organizational behaviour professor at McGill University's Desautels business school. "It becomes institutionalized."

Ottawa ordered striking CP workers back to work in 2012 after nine days off the jobs. Three years later they were back on strike, with many of the same issues still unresolved, including operator fatigue and minimum rest periods for workers between shifts, according to the union.

Ottawa has abandoned the long-standing federal practice of largely staying on the sidelines in labour disputes by repeatedly threatening back-to-work legislation, often pre-emptively, he said.

"This government has rewritten 60 years of labour policy," Prof. Hebdon said. "It's the only government I've ever seen that wants to end strikes almost before they've begun. They don't seem to like unions conducting strikes of any kind."

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Since 2010, Ottawa has directly intervened in labour disputes at Air Canada, Canada Post, Canadian National and CP – all federally regulated industries.

With the threat of back-to-work legislation hanging over negotiations, management has little incentive to make concessions at the bargaining table, Prof. Hebdon said.

"The threat of back-to-work legislation is always the worst option," NDP labour critic Alexandre Boulerice told reporters in Ottawa.

But Ms. Leitch said the government's top priority was getting commuters to work in Montreal, and keeping freight shipments and exports moving. She said a protracted strike would have cost the economy $205-million a week in lost output, although she did not explain how the estimate was calculated.

"We're doing this for the good of our country," Ms. Leitch said before the two sides agreed to resume bargaining. "Our economy must be protected. Our products must reach markets. Canadian jobs must be preserved."

Prof. Hebdon, however, suggested there is little evidence of a national emergency in any of these cases where Ottawa has gotten involved.

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Various industry groups warned that the strike was threatening to disrupt movement of various commodities and manufactured goods, including cars, crude oil, grain, minerals and forest products. "This decision ensures both sides will get back to the table, and gets us back to moving Canada's economy forward," CP chief executive Hunter Harrison said in a statement.