Over 2,000 Go Transit employees are on strike.
The Amalgamated Transit Union Local 1587 was unable to secure a contract with GO operator Metrolinx despite weekend negotiations. Key issues include job security and job safety relating to hiring contract workers from outside companies.
Workers impacted include bus operators and station attendants.
Union officials say the move comes after members voted 81 per cent against a previous contract offer.
Riders are encouraged to plan ahead and give themselves extra time for their commute.
The GO Bus runs from the Peterborough Transit Terminal on Simcoe Street.
(Written by: Jordan Mercier)

