MONTREAL -- Service has returned to normal on the Montreal metro's Green line between Angrignon and Lionel-Groulx after a shutdown late Tuesday morning.

The closure happened at about 11:50 a.m., and by 12:25 p.m., the transit authority said service is gradually resuming. It was back to normal by 12:40 p.m.

STM officials say the shutdown was due to a problem with equipment on the tracks.