VANCOUVER -- An issue on a major Metro Vancouver transit line was reported Monday afternoon, and TransLink says it won't be fixed until service is over for the day.

The service provider warned of some type of "track issue" causing problems on the Expo Line, but did not elaborate on what the issue was.

As a result, TransLink said initially, trains were only able to pass through the area between New Westminster and Sapperton stations on a single track.

Later in the afternoon, TransLink said the issue was affecting Columbia to Production stations. And in an email to CTV News Vancouver, a spokesperson said crews would have to wait until after service ended Monday to fix it.

Meanwhile, those trying to get to Production should transfer at Columbia, TransLink said, as all Expo Line trains from Waterfront Station were going to King George Station.

By 3:30 p.m. some stations and trains were crowded as those who rely on the SkyTrain waited for delayed trains.

The Millennium and Canada lines were unaffected, TransLink said.

It's not the first time in recent days that TransLink has had issues with the line. The transit provider had to suspend service Saturday due to a "technical issue" between Edmonds and Waterfront stations.

TransLink had planned track maintenance work for last week on the line, but said in a message posted on Twitter that the work was rescheduled for Monday.

The overnight maintenance is planned for between Main and Commercial-Broadway stations, and passengers are advised to plan for a 15- to 20-minute longer commute.

There were also issues last week on the Canada Line that impacted service.