TORONTO -- Thousands of commuters in the Greater Toronto Area can breathe a huge sigh of relief.

A strike that threatened to shut down GO Transit bus service this morning has been averted.

A tentative agreement on a four year contract was reached overnight as negotiations between Metrolinx and Amalgamated Transit Union Local 1587 continued past the midnight strike deadline.

The local represents 1,850 GO workers, including bus drivers, maintenance personnel, safety staff and some office workers.

Shutting down the bus service would have impacted an estimated 53,000 daily commuters.

Details of the tentative contract have not been released, and there's no word yet on a date for a ratification vote, however, it`s expected to happen some time this week.

Dan Harris, President of Local 1587 said in a statement issued early this morning "we are very pleased that a fair and equitable agreement was reached without any disruption to GO Transit service."