A major portion of the city's subway system is not expected to open until mid-afternoon Sunday as work continues on a new control signal system.

The Toronto Transit Commission (TTC) said the University line between Union Station and St. George Station will not operate until at least 2 p.m. as work continues on the new Automatic Train Control signal system. The underground usually begins operation at 9 a.m. on Sundays.

The TTC said shuttle buses will be available between Union and St. George stations, stopping at Union, St. Andrew, Osgoode, St. Patrick, Queen's Park, Museum and St. George stations.

It also said passengers can take the Yonge subway south, and transfer to a streetcar at College, Dundas, Queen or King stations. At Wellesley Station, customers can board the 94 Wellesley bus for an east or west journey.