Metro rail service on the Orrange Line was delayed in Arlington Tuesday evening while authorities investigated a report of a suspicious person on a train, authorities said.

Trains ran on a single track in the Ballston area while one inbound train was held there for the investigation, officials said.

The train was released by about 5:30 p.m. and service resumed on both tracks, but riders were told to expect delays.

Although the train was released, an investigation of the report was continuing, said Metro spokesman Dan Stessel.