Service on the Barrie-Toronto GO Train line was suspended Monday morning for a police investigation south of the Barrie GO station.

There will be no service on the Allandale Waterfront GO 5:50 a.m. train to Union Station as a result of the closure.

Three trains are currently holding on the rail line as the investigation proceeds.

"Trains will not be able to move through the area until given permission. Generally this will take about 3 hours until we can run our regular service," GO Transit said on its website.

Metrolinx spokesperson Vanessa Barrasa said the service recommends passengers take the Richmond Hill line instead.

"Please pack your patience because it will be slow this morning on the Barrie line," she said.