TransLink is defending its service record after experiencing its fourth major SkyTrain service disruption in three months.

Passengers were left waiting at the platforms Tuesday evening after system-wide delays hit the Expo and Millennium lines yet again.

The problem, which has been blamed on a single faulty modem, lasted nearly four hours.

TransLink spokeswoman Cheryl Ziola acknowledged that breakdowns can be frustrating, but said they need to be taken in context.

“We’re talking about five per cent of the time when things happen, and, you know, it’s no different from any other major transit jurisdiction,” Ziola said.

She pointed to recent a transit shutdown in Toronto that lasted six hours, and another in New York City caused by kittens on the tracks that stranded passengers for two.

“It seems really innocent but you know, it caused thousands of commuters to be late,” Ziola said. “There are things that happen that are beyond our control.”

Tuesday’s disruption completely cut service between Edmonds and Joyce-Collingwood stations, forcing crowds of commuters to wait for bus shuttles to get to their destinations.

TransLink eventually traced the issue to a modem in a computer that controls several track switches. The transit provider said the modem is less than a year old, and still under warranty.

“The modem is a more robust and commercial version of a regular consumer modem. The modem’s purpose is to communicate between field devices and our central control,” TransLink said in a statement.

“The supplier will do some analysis of the premature failure.”

The next day, a similar track switch issue disrupted service again. Fortunately, it was resolved in about 15 minutes.

Many riders have taken to social media to complain about the service, but Ziola said she’s not convinced the general public is losing faith in TransLink.

“That’s a bit premature, we need to have some numbers to back that up,” she said. “I don’t like to respond to a few tweets, I don’t necessarily think that’s a comprehensive style of survey.”

The transit provider does customer polling multiple times a year, and has seen 76 per cent satisfaction among riders in recent years, Ziola said.

Tuesday’s issue marked TransLink’s fourth major service disruption in three months, beginning with two full shutdowns in July that spurred a pricey $1,200 per day review into what went wrong.

The final report is expected to be released in October.

Canada Line service was not affected in any of the recent breakdowns.