Two arcing insulators at the Friendship Heights Metro station tied up Red Line trains Monday night, fire and Metro officials said.

The insulators were just south of the station’s platform, Metro said. Montgomery County firefighters were called to the station around 8:15 p.m. and by 8:49 p.m. Metro’s maintenance crews were in the process of removing the insulators.

These are some of the common mechanical problems reported on Metro that are a pain for riders. (Claritza Jimenez/The Washington Post)

Richard Jordan, a Metro spokesman, said normal service should resume shortly.

It’s not clear how officials were alerted about the insulators, but Pete Piringer, a spokesman for the Montgomery County fire and rescue department, said there was no smoke or fire at the station.