All MARC trains canceled Friday morning after system outage

All MARC trains, which primarily run between Maryland and Washington, D.C., were canceled on Friday morning after the system suffered a communication outage.

"All MARC Train service continues to be suspended due to a system wide communication outage," the Maryland Transit Administration (MTA) said in an alert on Twitter. "Currently there is no estimated time for restoration of service. Technicians continue working to restore service."

Nearly 20 trains had been cancelled as of 8 a.m., according to MTA’s service alerts on Twitter.

MTA Administrator Holly Arnold said in a tweet that all three MARC lines — Brunswick, Camden and Penn — had been affected by a positive train control (PTC) communication issue.

PTC systems are used to "prevent train-to-train collisions, over-speed derailments, incursions into established work zones, and movements of trains through switches left in the wrong position," according to the Federal Railroad Administration.

"I know how inconvenient this is and our team is working to resolve as quickly as possible to provide service this morning," Arnold added. "Please consider Commuter Bus or @wmata options in the meantime."