UPDATE: Regular service resumes on Line 1

The work car that derailed near St. George Station

Toronto Mayor John Tory is calling for an investigation into how the city's transit agency handled a derailment that shut down a stretch of a major subway line.

The Toronto Transit Commission says a work car derailed around 5:30 a.m. at St. George station and stopped service between St. Clair West and Union stations.

Nobody was injured in the incident.

The aftermath of the derailment clogged much of the transit system during the morning rush, and Tory says a lack of communication may have added to that.

A TTC spokeswoman says shuttle buses were put in place, and the agency has also added extra buses and streetcars on alternate routes, to help with the backlog.

But Tory says details of the delay weren't shared with transit workers or members of the public quickly or effectively enough.

Regular service was restored seven hours after the train jumped the track.