The rush-hour commute on the Metro’s red line ground to a halt this morning.

At around 8:45 a.m., a spark on the “electrified third rail” sent smoke through the Union Station stop.

While there was no real fire or flames, the situation prompted Metro Transit Police and the D.C. Fire Department to evacuate Union Station at about 9 a.m., Metro spokesman Dan Stessel said.

Red line trains were also stopped, and conductors asked customers to please be patient.

The station reopened at 10 a.m. after the smoke had been vented out of the system, Stessel said.

No injuries have been reported. Red line trains are now running with some delays.