GO Transit says one of its trains on the Barrie line is out of service after experiencing mechanical problems at York University.

The train departed Union Station at 3:40 p.m. but stopped at York University after it blew a gasket in one of its air brake valves, rendering it inoperable, Metrolinx spokesperson Anne Marie Aikins said.

Passengers were let out of the train and it was moved out of the way around 4:45 p.m., about 35 minutes after it stopped, so it did not block other northbound trains passing through the same corridor.

Aikins said shuttle buses are on the way to pick up stranded passengers.

Buses will take passengers to Rutherford GO station so they can board later northbound trains.