05/21/2013 05:14 EDT | Updated 07/21/2013 05:12 EDT

Service restored on Montreal metro lines

The STM is reporting that Montreal's metro service has been restored across all four lines.

The public transit corporation announced an outage across the metro system at about 4 o'clock just as the afternoon rush hour was getting into full swing.

The outage lasted about 40 minutes.

The STM was investigating whether its computer system was responsible for the disruption across its system. There have been outages in the past due to the computers.