The Washington Metropolitan Area Transit Authority is pulling about 60 percent of Metro trains from operations Monday after a train derailed near Arlington Cemetery last week, creating service delays at all Metrorail stations.

The Washington Metrorail Safety Commission ordered on Sunday that WMATA remove 7000-series trains from service until they inspect and confirm the safety of the railcars. The axle assembly on the derailed train was “out of compliance” with safety standards and investigators found similar defects on several other railcars not involved in the derailment, the order states.

WMATA announced that rail service would be significantly delayed on all lines as a result of the reductions, with trains departing each stop about every 30 minutes, according to a release.

“As part of the investigation into the Blue Line derailment, Metro is holding out of service all of its 7000-series railcars, which is about 60 percent of its rail fleet,” WMATA said in the release. “Without these rail cars, Metro will operate about 40 trains tomorrow.”

WMATA officials said they will soon update customers with service details for the remainder of the week. It is unclear when the trains will be put back into service.

The National Transportation Safety Board is investigating the derailment, which caused the Blue Line to be closed between Rosslyn and the Pentagon for two days. WMATA spokesperson Ian Jannetta said in an email that the NTSB is holding a briefing Monday morning with Chair Jennifer Homendy and investigator Joe Gordon  to provide an update on its investigation.

There were no injuries in the derailment except for one woman who was sent to the hospital as a precaution because of anxiety issues, the Washington Post reported.

WMATA purchased nearly 750 7000-series railcars from the Japan-based Kawasaki company between 2010 and 2013 to replace decades-old 1000-series railcars, the Post reported.