Service has resumed on the Toronto and Hamilton area's commuter rail system after a power outage brought all trains to a halt for hours during Friday's morning rush.
GO Transit warned, however, that travellers would still experience delays as the company worked to bring trains back on schedule.
The transit company said an outage at the CN rail control centre had caused signal failures throughout the system, preventing radio communication and forcing all trains to stay put for more than an hour.
Power was restored shortly before noon, but only some signals were working at first, meaning not all trains were able to get back on the move immediately.
GO Transit says it runs 252 weekday train trips carrying an average of 215,000 passengers.
It also operates a network of commuter buses, which were unaffected by the power outage.