The Green Line was delayed Saturday morning due to a medical emergency at the College Park Metro station.
Prince George's County Fire Department responded to a "sick person call," but "did not transport anyone" said fire department spokesman Mark Brady.
Brady did not provide any additional details about the sick person.
WMATA warned commuters to expect delays on the Green Line in both directions at 11:24 a.m, according to their Twitter account. Green Line trains began single-tracking between Greenbelt and College Park Metro stations.
Less than 10 minutes later, WMATA announced an end to singe tracking, but warned of residual delays due to the earlier emergency.
At 11:51 a.m., WMATA tweeted normal service had resumed at College Park Metro station.