If your weekend plans involve taking the train into or out of Toronto, pray for smooth contract negotiations tonight.

Via Rail and Metrolinx both warned passengers on Friday that service could be delayed or cancelled this weekend on account of a labour dispute between Canadian Pacific Railway and two of its unions.

A potential CP Rail work stoppage could have some impact on GO train services starting as early as this Saturday. To see what lines may be impacted, click here: https://t.co/6o3xU1IdT7 pic.twitter.com/Th3V3Bihle

— Metrolinx (@Metrolinx) April 20, 2018

A strike deadline has been set for April 21, meaning that 3,000 unionized conductors and engineers will walk off the job at 12:01 a.m. if an agreement can't be reached by midnight on Friday.

Negotiations between management and workers have reportedly stalled, making the prospect of a strike — the third in six years for CP Rail employees — more likely than not.

On the GO train and conductor just made an announcement about CP railworkers possibly going on strike. All smiles. Reminder to always back strikers, always back labour, always back workers. If it bothers you you're an asshole, period.

— Noman Siddiqui (@noman_sid) April 20, 2018

Via Rail said in a statement on Friday that, should a strike be called, it may have to cancel morning trains on Saturday and Sunday between Sudbury and White River, Ont.

Metrolinx said similarly that there could be delays for customers on its Milton and Barrie lines, according to the Canadian Press, "if CP Rail managers filling in for union workers are unable to address signal or switch issues on CP Rail-owned portions of the corridors."