Service has resumed on most GO trains across the GTA and the Union-Pearson Express after a power outage downtown that caused major delays.

Thousands of commuters were affected by residual delays after a massive outage at the CN control tower.

“I’m happy to report we are ready for rush hour,” Chief Operating Officer of Metrolinx Greg Percy told the media on Friday afternoon.

“The key thing was to get the UP Express back up and to deal with any customers that were stranded.”

Around 18 people were affected on the UP Express and some of them missed their flights, Percy said.

He estimated 2,000 customers were stranded on GO Service trains, mainly on the Lakeshore line.

After trains started up again, there was a second suspension, which Percy said was “rare.”

He said this was an issue with software, not physical hardware.

The system had to be rebooted and power had to be restored “train by train,” according to Percy, which is why the delay lasted so long. Percy said he was not yet certain what cause the outage.

One train carrying UP Express passengers was stuck near Weston Station due to the power outage for over one hour.

A passenger on the UP Express train Scott Greenwood told CTV News Toronto that he missed his flight from Toronto to Vancouver.

Still stuck on train at around 11 a.m., Greenwood said he had missed his flight which left at 10:40 a.m. and he was on the UP Express at 9 a.m.

Greenwood said this is “not a great way to start a vacation.”

Those who missed their flights due to the disruption are encouraged to call Metrolinx.