About 2,800 members of the United Transportation Union employed by CN walked off the job early Saturday after negotiations in Montreal broke down.

The strike isn't expected to affect Via Rail service or commuter trains in Montreal and Toronto.

CN filed a complaint with the Canada Industrial Relations Board Saturday morning claiming the union's pressure tactic is against the law.

“The UTU International, which is the certified bargaining agent for the employees, has not authorized this strike,” said CN spokesperson Mark Hallman.

The union admits that while its international president — who is based in the U.S. — has not provided authorization, it does not affect the legality of the strike.

“There is definitely a dispute internally with the Canadian portion as compared to our American parent,” said the union's chief negotiator, Rex Beatty. “But what you have to look at is the constitution of the union cannot supersede the law.”

Mr. Beatty said the principal issues at stake are what he calls “harassment and intimidation” issues.

Late Saturday, the union that represents CN Rail's locomotive engineers said they had also filed a complaint with the Canada Industrial Relations Board — against CN.

The Teamsters Canada Rail Conference said in a news release that CN is “attempting to unilaterally change working conditions (and work functions) of locomotive engineers” as a result of the strike.

They say these changes are against their collective agreement with CN.

The organization said they're asking the board to order CN to stop any “any continued or further breaches of the Canada Labour Code,” and to reimburse the union for costs associated with the alleged violations.

They also said they're in full support of the United Transportation Union's action against CN.

The United Transportation Union is seeking a 40-minute lunch break on nine-hour shifts instead of the current 20-minute break. It is also seeking a 4.5 per cent wage increase over two years, along with 4 per cent increase in the third year of the contract.

Mr. Hallman wouldn't comment on the union's demands, saying the company does not want to negotiate through the media.

But with the strike barely one day old, it already has the makings of an acrimonious dispute.

CN says it is attempting to sue union leaders for damages caused by the strike. The union claims the company is also trying to force workers back to work by telling them the strike is illegal.

“The problem with that is they got the cart ahead of the horse,” said Mr. Beatty, pointing out that the industrial relations board has yet to rule on the legality of the walkout.

Mr. Beatty expects the board to rule on the strike in the coming days.

CN plans to continue its freight operations across Canada during the dispute, with management personnel performing union jobs.

“CN regrets that this strike has happened, but we are prepared to operate with management personnel... for as long as it takes,” Mr. Hallman said.

Mr. Beatty was skeptical about how long management would be able to keep CN's freight network running.

“The system will implode, it will come to a grinding halt,” he said. “It may take a few weeks, but it will definitely happen.”

The Canadian Wheat Board, the single largest rail shipper in Western Canada, has already expressed fears the dispute could result in delays for clients.

The board's President and CEO Greg Arason told the Winnipeg Free Press on Saturday that he expects that some trains won't make it.

“It's definitely a major concern for us,” the Winnipeg-based Mr. Arason said from Vancouver.

“We have been in a backlog situation with shipments to the West Coast. We already have ships waiting, and this will make it worse.”

No new negotiations between the two sides are scheduled.