TORONTO -- Two passenger trains are back on the move after being held for several hours at Toronto's Union station over concerns that a nearby building might collapse on the tracks.

A spokeswoman for Via Rail confirms service has resumed but says she doesn't know whether the trains are being rerouted or the building has been stabilized.

Elizabeth Huart says one of trains came from Sarnia and was stopped outside the station for nearly two hours until officials gave it the go-ahead to continue.

She says the train's 116 passengers were originally supposed to arrive at Union station by 10:50 a.m. but didn't disembark until just before 1 p.m.

The second train, which carried 85 passengers, was scheduled to leave for Sarnia at 10:15 a.m. but pulled out of Union station around 1 p.m.

Huart says the holdup stemmed from worries surrounding a building being demolished near a stretch of the tracks.

It's unclear whether any other trains will be delayed.

Union station is a major commuter hub in Toronto, used by up to 200,000 passengers each day.