Summer travel has been derailed for many Canadians now that the union representing Via Rail's 340 locomotive engineers said the workers have walked off the job.

The union made the announcement Friday shortly after a noon deadline for a deal in the ongoing contract dispute passed without a settlement.

The engineer walkout effectively shuts down the bulk of national passenger rail service across the country.

Via and the Teamsters Canada Rail Conference union had been in intense talks all week to try to ward off a strike, but contract negotiations broke down overnight. The union issued a strike notice early Friday saying it would hit the picket line at noon Friday, unless something changed.

The train engineers have been without a contract since Dec. 31, 2006. A federal mediator had been appointed to help broker a deal, and until Friday both sides said they were hopeful a deal could be reached.

But Via released a statement early Friday saying talks broke down around 1 a.m. ET.

"Despite intense negotiations over the past four days, the parties were unfortunately unable to reach an agreement, and the negotiations are currently at an impasse," the Via statement read.

"Barring a last-minute resolution, Via will have no choice but to cease operations of Canada's national passenger rail service as of Friday, July 24, 2009 at noon ET."

Via Rail said alternate transportation was to be provided where possible at intermediate stations for passengers scheduled to depart before noon ET. After that, said Via, no alternate transportation would be provided.

The only exception was for passengers travelling from Jasper to Vancouver.

Some trains were already cancelled this week in anticipation of a strike, such as those leaving and arriving Halifax.

Passengers whose train travel is affected can obtain a refund for unused tickets.

Greyhound bus lines has said it will respond to increased demand by adding buses if needed.

Via carries close to 12,000 passengers every day in Canada; up to 85 per cent of its business is between Quebec City and Windsor.

Ripple effects from the strike are expected to be felt across the country. Taxi drivers in Ottawa, who depend on traffic from the local train station for a significant portion of their income, say they expect to lose $100 to $200 a day as long as train service is suspended.

The strike comes during one of the busiest travelling periods of the year, dealing Canadian tourism operators already struggling amid the economic slowdown yet another hit.

Via has said its ticket counters are to remain open for the next few days, presumably to handle refunds, and that it's currently not accepting bookings.

Meanwhile, negotiations continue. Shortly after the strike commenced on Friday, a spokesperson from Via said representatives from the company and the union were continuing to meet with mediators.