CN Raillocked out hundreds of unionized employeesWednesday afternoon after theybegan rotating strikes at five locations across Canada.

The dispute flared upagain after union members rejected a tentative dealstruck in February to end a 15-day walkout.

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Union representative Scott Montani says labour action will rotate among various Canadian cities to keep freight moving. ((CBC))

United Transportation Union workers in Ontario, British Columbia and Nova Scotia beganrotating strikes late Tuesday to force Canada's largest rail carrier to return to the bargaining table.

ButCN said it would lock out all 280 workersin locations where picketing had been taking place: Vancouver, Kamloops, B.C.,and inthe Ontario communitiesofOakville, Brantford and Aldershot.

"CN is a scheduled railroad and we cannot run scheduled freight operations without scheduled manpower," CN spokesmanMark Hallman said.

GO Transit — the commuter train service that serves Toronto and surrounding communities, including Oakville—has so far been able to run its trains without the CN dispute causing major problems. The union must give three days notice if it plans to withdraw service from GO.

'It's not about hurting businesses'

Union representative Scott Montani told CBC News in the morning thatthe labour action would rotateamong variousCanadian cities in order to ensure freight keeps moving.

"It's not about hurting Canadian businesses. It's about getting CN back to the table. The union doesn't want to hurt anybody," Montani said, adding that the strikeswould not disrupt commuter service.

Picket co-ordinator David Moorhouse said workers want to send CN the message that more money and a safer workplace are key.

"We're going to do what it takes to get CN back to the table. We don't want to disrupt the network," he said.

Hours before the lockout announcement,CNsaidit was preparedto return to the bargaining table, but warned it would not change the substance of its offer.

"CN is prepared to meet the union," said spokesman Mark Hallman.

"They are interested in renewing talks and at the end of the day we just need to take a look at what the parties are talking about and see if we can make progress."

Earlier walkout hurt industries

Federal Labour Minister Jean-Pierre Blackburn said the government has back-to-work legislation ready to go if it is needed.

The legislation was tabled in the House of Commons on Feb. 24, before the tentative deal was worked out to end a 15-day strike byCN's conductors and yard-service workers. That walkout crippled freight service and took a serious toll on some industries.

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CN Rail workers picket in Vancouver Tuesday night.

"A negotiated settlement is always preferable to legislation," Blackburn said in a news release.

However, back-to-work legislationmight be held up because the Commons is on an Easter recess until next Monday.

Nearly 80 per cent of the United Transportation Union workers who cast ballots voted against the agreement Tuesday night. Voter turnout for the 2,800 members of the union was about 84 per cent.

The union's Canadian leadership had recommended that members endorse the one-year deal, retroactive to Jan. 1,that was to provide a three per cent wage hike and $1,000 signing bonuses.

Hallman said the company has a contingency plan. The company has said it will be usingmanagers tokeep the system running.

"We're going to provide the best level of service we can," Hallman said.

With files from the Canadian Press