Railroad workers at Canadian National are preparing for a strike Monday after returning to work following Thursday’s lockout.

Teamsters Canada Rail Conference on Friday served the railway company with a 72-hour notice that 6,500 workers intend to strike on 10 a.m. Monday.

The announced strike would occur just days after Canadian Labor Minister Steven MacKinnon ordered the Canada Industrial Relations Board to impose binding arbitration between the parties, whose contract dispute resulted in workers being locked out in the morning and most of the afternoon on Thursday.

“We do not believe that any of the matters we have been discussing over the last several days are insurmountable and we remain available for discussion in order to resolve this matter without a further work stoppage,” the notice said.

The union, in a release late Thursday night, had said workers would begin returning to work on Friday morning following the lockout. But if a strike were to occur Monday, rail traffic would once again halt. 

Rail service at Canadian Pacific Kansas City, the other railroad that initiated a lockout Tuesday due to a contract dispute with the union, has not yet resumed.

The company, in a press release late Thursday evening, said it was “fully prepared to address the resumption of service given its obvious priority” at a case management conference held by the Canada Industrial Relations Board, but said the union “refused to discuss” that topic and instead expressed intent to challenge the constitutionality of the Minister’s order to end the dispute. 

Any decision to resume rail service by the Canada Industrial Relations, the release said, “will be delayed.”

“CPKC remains prepared to resume service as soon as it is ordered to do so by the CIRB,” the release said. 

As rail users wait for a resumption of service, shipping containers are stacking up at ports along parts of the West Coast, including Seattle and Tacoma, said Ag Transportation Coalition Executive Director Peter Friedmann. Similar things are happening at rail ramps in Minneapolis, Chicago and other parts of the Midwest, leaving shipments of things like grain unable to move. 

“When they get backed up and nothing moves out, nothing more can come in and vice versa,” Friedmann told Agri-Pulse. “That has already happened.”