The city can't figure out why the water main burst and flooded the metro

Major water main break causes metro mayhem Thousands of Montreal transit users were stuck in the metro Thursday morning as a leak shut down a large part of the orange line

MONTREAL -- Work is continuing on a water main under Viger Street after it burst Thursday, bringing service on part of the Orange Line to a grinding halt.

The repair job is a tricky job one: the pipe is under another 76-centimetre-wide water pipe and next to electrical lines.

The infrastructure was last checked out in August, so the city is trying to determine why it suddenly ruptured.

"I know for sure it's not the cold weather that we got this week, because it's too deep in the ground, so the weather is not an issue, it's not a concern. We know that for sure it's not aging infrastructure -- it's all new," said City of Montreal spokesperson Philippe Sabourin.

As many as 200 homes in the area remain without water and part of Viger near Victoria Square remains closed.