Thousands of Metro riders in downtown Washington waited on packed platforms for heavily crowded trains during Monday’s evening rush after a rail-switch problem curtailed service on the Blue and Orange lines.

After the problem was detected about 11 a.m., trains traveling in both directions used one track between Foggy Bottom and Farragut West. Two tracks were used for the evening rush, but speeds were reduced and waits for trains were longer.

Metro said waits between trains were estimated at about 10 minutes, instead of the normal six, on both affected lines. Repairs and single-tracking were to resume Monday night, Metro said.

Crowding appeared to peak at the Farragut West station about 6 p.m. Micah Himmel, a Metro rider, said a “massive throng” was backed up from the platform onto the escalators and “way past” the fare gates. A photograph showed a crowd about 10 people deep filling the platform.

The crowd swelled further when passengers were taken off an arriving train that had a door problem.

Metro Transit police were sent to key stations to keep people from platform edges, system spokeswoman Morgan Dye said. Some trains entering crowded downtown stations were described as so full that few passengers could board.

By about 7 p.m., it appeared that the crowds had largely diminished. Metro said it expected normal service Tuesday morning.