A minor Metro track fire led to a Red Line service disruption early Sunday morning.

Metro received reports of a wooden crosstie smoldering north of Union Station around 6:30 a.m., said spokeswoman Morgan Dye. Initial attempts by Metro workers to extinguish the fire failed, and District firefighters were called in, she said.

Red Line trains were single-tracked through the area while firefighters worked, Dye said, and regular service was restored around 9 a.m. Riders did not encounter significant delays, she said, due to the weekend schedule.

Dye said minor track fires are “fairly routine” occurrences and that the incident was not related to the fatal welding accident that occurred in the Red Line tunnel south of Union Station two weeks ago.