Locomotive engineers and conductors at Canadian Pacific Railway went on strike early Wednesday after failing to reach a contract agreement, shutting down freight operations on Canada's second-biggest railroad.

The union and CP Rail said talks will resume in the morning.

"We will not walk away from the negotiation table," said Doug Finnson of Teamsters Canada Rail Conference, which represents the engineers and conductors at CP Rail.

The stoppage means that shippers in Canada, including farmers, miners and retailers, will have to find other means to move their goods or will find their wares stranded.

"In addition to customer and supply chain impacts, the suspension of CP's freight service will also impact many of the connecting railways with whom we do business," a CP spokesman said in a statement.

Commuter service continues to operate without disruption in Vancouver, Toronto and Montreal, despite the strike, the spokesman said.

But some commuters are being affected in eastern Ontario. The strike means Via Rail cannot operate on tracks where CP is the host railway, Via said in a release. So passengers whose routes take them between Ottawa and Brockville, Ont., will travel on shuttle buses, though train service continues as normal west of Brockville and east of Ottawa, according to a notice on the Via Rail website.

Service to and from destinations east of Ottawa shouldn't be affected by the strike.

About 4,800 engineers, conductors and traffic controllers at CP, nearly a third of its workforce, walked off the job after last-ditch talks on Tuesday didn't result in a new labour contract.

Employees have been without a contract since the end of last year and have been in talks with CP since October 2011.

The strike comes at a difficult time for CP. Its chief executive quit on Thursday in the face of a boardroom coup led by CP's biggest shareholder, who is demanding that the railway improve its operating performance, currently the worst in the industry.

- With files from Tony Spears