Christopher Reynolds and Jordan Omstead, The Canadian Press

Freight trains must start rolling again first thing Monday morning, the federal labour board ruled Saturday as it ordered thousands of rail employees back to work to end a bitter contract dispute that shut down the country's two major railways.

The decision from the Canada Industrial Relations Board imposes binding arbitration on all involved parties following an unprecedented dual work stoppage at Canadian National Railway and Canadian Pacific Kansas City that halted freight shipments and snarled commutes across the country.

But the matter may not be settled for good, since the Teamsters union representing workers with both companies is pledging to appeal the ruling in court.

The board's decision dropped two days after Labour Minister Steven MacKinnon directed the arm's-length tribunal to begin the arbitration process, saying the parties were at an impasse and Canadian businesses and trade relationships were at stake.

The union representing the 9,300 affected workers challenged the government's move before the board, but the tribunal said it had no authority to decide whether the minister's directive was valid.

"The board has concluded that, in this case, it has no discretion or ability to refuse to implement, in whole or in part, the minister’s directions or to modify their terms," wrote chairwoman Ginette Brazeau in a pair of rulings.

Brazeau ordered the two companies and the engineers, conductors, dispatchers and yard workers concerned to resume operations starting at 12:01 a.m. on Monday.

On top of ending the lockout and simultaneous strike at CPKC, the ruling effectively voids the 72-hour strike notice to CN the union issued on Friday morning.

The Teamsters said they will comply with the tribunal's decision but plan to file a court appeal, arguing it "sets a dangerous precedent."

"It signals to corporate Canada that large companies need only stop their operations for a few hours, inflict short-term economic pain and the federal government will step in to break a union," said Paul Boucher, president of the Teamsters Canada Rail Conference.

"The rights of Canadian workers have been significantly diminished today," he said in a release.

Canada's largest railway said it aims to ramp up shipments as quickly as possible.

"While CN is disappointed an agreement could not be reached at the bargaining table, the company is satisfied that this order effectively ends the unpredictability that has been negatively impacting supply chains for months."

Canadian Pacific said it has ended the lockout it imposed on employees Thursday morning and asked them to return to the job on Sunday to "avoid further disruption to supply chains."

A union spokesman said it declined the company's request to return before Monday — despite the labour minister's statement Saturday that he expected "railway companies and employees will resume operations at the earliest opportunity."

"The CIRB order ends months of unnecessary uncertainty and disruption for the Canadian economy," CPKC said in a release.

The company said it expects full recovery to take several weeks, noting a phased shutdown at both railways kicked off roughly two weeks ago. As the negotiating clock ticked down, carriers became wary of leaving cargo — from meat to medicine, chlorine and other dangerous goods — stranded on the tracks in the event of a work stoppage.

The labour board ruled that binding arbitration will begin on Aug. 29.

Cargo traffic and some commuter lines across Canada came to a standstill on Thursday when CN and CPKC locked out workers after months of increasingly acrimonious contract talks failed to yield a deal.

It marked the first time simultaneous work stoppages struck the railways.

CPKC workers went on strike at the same time a lockout came into effect early Thursday morning, with its yards still shuttered on Saturday. CN lifted its lockout on Thursday, and freight service began to rev up on Friday morning.

The Teamsters have said both companies are attempting to weaken protections around rest periods, shift length and scheduling, jeopardizing worker safety. CN also has a plan to move some employees to far-flung locations for several months at a time to fill labour gaps, the union says.

(C) The Canadian Press