GO Transit commuters faced long delays and some cancellations this morning after a computer failure at CN caused signal problems across GO's rail network.

By 9:30 a.m., service was staring to return to normal with some residual delays, particularly on the Lakeshore East line where trains were running up to 30 minutes late.

Earlier, however, there were widespread delays and some cancellations across the GO network.

"I'm sure this was no way people wanted to start a beautiful Friday morning," said Metrolinx spokesperson Anne Marie Aikins in an interview on CBC Radio's Metro Morning.

She said it took about 45 minutes for CN to fix the original computer problem. From there, delays and cancellations began to multiply during the busiest part of Friday's morning commute.

"By the time they got it switched over and rebooted ... it caused a great number of delays."

The problems were worst on GO's Lakeshore East and Lakeshore West lines, where GO has a 30-minute service commitment. Any trains delayed longer than 30 minutes are automatically cancelled.

​Aikins said the delays should not affect passengers travelling on GO to attend tonight's Opening Ceremony of the Parapan Am Games.

Below is the latest closure information from the service update page on GO's website, which was last updated at 9:43 a.m.

Lakeshore West

The Aldershot GO 08:31 - Union Station 09:41 train is cancelled. The next scheduled train is the Aldershot GO 09:01 - Union Station 10:11 train.

Lakeshore East

The Pickering GO 08:25 - Union Station 09:10 train departed Pickering 24 minutes late.

The Union Station 07:50 - Oshawa GO 08:48 train is delayed 16 minutes from Ajax.

The Union Station 07:28 - Oshawa GO 08:26 train is on the move 53 minutes late west of Whitby.

The Union Station 08:13 - Oshawa GO 09:11 train is 16 minutes late east of Ajax due to the earlier signal failure.

The Pickering GO 07:55 - Union Station 08:42 train arrived into Union 39 minutes late.

The Oshawa GO 09:38 - Union Station 10:41 train is cancelled due to the earlier signal failure. Next train is the Oshawa GO 10:08 - Union Station 11:11 trip.

The Union Station 09:17 - Oshawa GO 10:15 train left Union 18 minutes late as a result of the earlier signal failure.

The Oshawa GO 08:25 - Union Station 09:18 train arrived Union 23 minutes late.

Kitchener

The Bramalea GO 09:39 - Union Station 10:20 train is delayed 9 minutes from Bramalea due to an earlier computer failure affecting the signals.

Stouffville

The signal problem on this line has been resolved, but there are some residual delays.

Richmond Hill