There are no Metro station closings this weekend, but crews will be working on four lines. (Robert Thomson - Washington Post) (Robert Thomson/The Washington Post)

This post has been updated.

At noon, Metro said it had fixed all of its computer problems that impacted customers Thursday morning and it had also dealt with a number of hiccups on four of its rail lines.

The cause of the computer troubles “has not yet been determined,” Metro said.

At 11:30 a.m., a news alert went out from Metro that said its Web site, customer information and transit police phone lines, NextBus system, MetroAccess call center and the signs in stations that tell when the next train is coming have been fixed. But it cautioned that its “live operator assistance” by phone may still be unavailable for some customers.

They also said technicians “have been working to isolate and resolve the problem.”

Earlier in the morning, Metro officials said the agency’s internal computer systems were having problems Thursday morning, but that the problems were not affecting train or bus service.

Metro spokesman Dan Stessel wrote in an e-mail just before 11 a.m. that “we do not yet know the cause.” He said “the issue is being resolved now. It does not affect any rail safety critical system.” He also said Metro had full radio “communication with its police, rail, stations and buses.”

In an earlier news release, Metro said it was having “intermittent network issues” that are affecting customers. The agency said the issues don’t impact “safety-critical systems.”

Displays at platforms inside stations are not working. The agency’s Web site also has been down. And there has been trouble with the customer information center phone lines, although those are said to be working again.

Metro said its “operations control center is able to communicate with all trains and all stations.”

Metro encouraged customers to follow updates on its Twitter accounts of @metrorailinfo, @metrobusinfo and @wmata.

Metro Transit Police also were having trouble with their customer telephone lines. Customers were urged to call 911 to reach officers if needed.

Computer problems weren’t the only troubles Metro was having Thursday morning.

The Red, Green, Orange and Yellow lines all had problems with trains that caused delays for passengers. On the Green and Yellow lines, trains were delayed because of a train at U Street that had a brake problem. The Red Line had a signal problem and then a track problem, causing delays. And the Orange Line had a switch problem at West Falls Church.

The problems on the rail lines caused many riders delays of up to 15 minutes.