The union representing about 3,000 conductors and locomotive engineers at Canadian Pacific Railway Ltd. says it has formally served the company with a 72 hour notice of an intent to strike.
The Teamsters Canada Rail Conference cites a lack of progress at the bargaining table but says talks are set to resume on Wednesday.
The union says should the two sides fail to reach a negotiated settlement, the workers will walk out at 12:01 a.m. on Saturday, April 21.
Canadian Pacific workers voted 94.2 per cent on April 6 in favour of strike action to support their contract demands.
The previous contract expired at the end of 2017 and federal mediators were brought in on Jan. 29, 2018.
The Teamsters reached a tentative deal with Canadian National Railway Co. last month for a new contract for about 1,700 CN locomotive engineers in Canada. Voting on that tentative deal is underway.