Orange Line riders faced extra-long waits for trains and crowded platforms during the Tuesday morning rush hour as Metro crews did emergency work on their tracks.

Trains single-tracked between East Falls Church and West Falls Church all morning as workers repaired signal equipment, which Metro spokesman Dan Stessel said was damaged after being hit by a train during overnight Silver Line testing. The train had no riders.

Metro said most Orange Line riders experienced delays of up to 15 minutes.

"Vienna station is completely packed, one train on the platform, and it's been here for 20min," tweeted rider Kyle Curd around 8 a.m., using the Twitter handle @kcurd8Tsix.

The repairs were expected to be complete by midday, but were still ongoing as of 12:20 p.m.

Stessel said the Metropolitan Washington Airports Authority, which is constructing the Silver Line, was not involved in the incident.