6:27 p.m. Update:
Red Line problems continue. Trains heading to Shady Grove are experiencing delays due to a train malfunction at Dupont Circle.
6:09 p.m. Update:
6 p.m. Update:
It appears the sick customer suffered a heart attack, according to the Metro Transit Police:
Red Line trains are sharing a single-track between Judiciary Square and Union Station due to a sick rider at Union Station, creating major delays in both directions.
— Cookie (@cookmain) January 8, 2014