A Metro train with passengers on board was struck early Thursday by a piece of track equipment, the second time in less than a week that crews at the transit agency have had problems while working on rail system repairs.

Around 12:38 a.m., a piece of equipment called a “movable arm” hit a passing train on the Blue Line in an area known as Potomac Yard between the Braddock Road and National Airport stations, according to Metro officials. Crews were working to replace ties along the tracks.

No passengers were injured. Caroline Lukas, a Metro spokeswoman, said passengers were delayed about 40 minutes while Metro conducted a safety inspection of the train. The crew involved in the incident was “immediately suspended and taken out of service,” Metro said.

On Sunday, a contractor was killed and two Metro workers were seriously injured when a fire and explosion in a tunnel near Union Station on the Red Line triggered other problems. The workers had been brought in to do maintenance on the tracks.