Testing along tracks for Metro’s new Silver Line touched off major rush-hour delays Tuesday morning for riders on the Orange Line.

The problem began at about 4 a.m., before the system was open to the public, as crews were running a train to test equipment near the East Falls Church station, where the future Silver Line will break off from the existing Orange Line.

The train had turned around at the East Falls Church stop and was making its way back to the rail yard at West Falls Church when the brake on one of its wheels began to lock, according to several Metro employees familiar with the situation. The employees spoke on the condition of anonymity because they were not authorized to speak publicly.

Hoping to clear the track before the system opened to the public at 5 a.m., the crew didn’t stop the train, which is from the system’s oldest series of rail cars.

But the wheel wore down as it ran along the track, causing a metal flange to fall out of place and sever 60 cables that are part of the signal equipment system. Known as C-bonds, the cables transmit signals about trains’ speed and location.

Without working signal equipment, trains couldn’t run through that area.

Repair crews arrived just before 5 a.m. and Metro said the problem would be fixed by midday. But it took crews nine hours to complete the work.

Dan Stessel, Metro’s spokesman, said it did not appear that the incident resulted in any damage to the new Silver Line track. Metro officials said there was no evidence that the train had derailed and that the cause of the mishap was under investigation.

Metro sent its first alert about the incident at 5:30 a.m., warning riders that trains were single-tracking. Two additional alerts went out between 6 a.m. and 7 a.m.

But some riders said there was little information from station managers and train operators of how long the delays would last. Others reported delays that were far longer than the 15 minutes Metro had advised. Many riders also said that trains and platforms were overcrowded.

Three of Metro’s other four lines experienced notable problems on Tuesday.

At 5:39 a.m., a train malfunction at L’Enfant Plaza affected the Yellow Line. At 1:14 p.m., there was a track problem on the Blue Line that lead to single-tracking between the Stadium-Armory and Morgan Boulevard stations. At 3:55 p.m., there was a train malfunction at Fort Totten on the Green Line. None of the incidents caused major delays.

The Orange Line incident comes as Metro has plans to soon retire the 1000 rail car series, which is the oldest fleet it owns, and replace them with its new 7000 rail car series. The 1000 rail car series has been in use since the system opened more than 30 years ago and were involved in Metro’s deadliest crash, along the Red Line in 2009.