A computer glitch that interfered with train signals created major delays for GO passengers on the Lakeshore West, Kitchener, Richmond Hill, Barrie and Milton lines during Thursday morning's commute.
GO Transit said train signals weren't working due to a malfunction involving a CN Rail computer system, creating delays of an hour for some passengers.
CN Rail eventually resolved the issue and signals began working again, allowing GO Transit to begin clearing the backlog.
Passengers at GO stations reported large crowds and long lineups of unhappy customers while the delays were at their peak.
When rail signals aren't working, train operators must bring their trains to a stop and wait for someone to give them the OK to proceed.
