A broken rail caused delays on Metro\'s Blue and Yellow lines for Thursday morning\'s rush hour.

WASHINGTON – The cold weather hitting the D.C. area is doing more than chilling the region — it’s affecting the Metro’s rails, too.

The frigid weather is to blame for a broken rail on Metro’s Blue and Yellow lines during Thursday morning’s rush hour. Crews repaired the rail by about 8 a.m. Thursday.

The broken rail caused delays for Metro riders between Braddock Road and the Ronald Reagan Washington National Airport stations.

The broken rail was south of the airport and required that crews install a new 39-foot section of rail, according to Metro.

Trains on the Blue and Yellow lines were running on a single track between Braddock Road and the airport stations until repairs are completed.

Sharp changes in temperature can cause broken rails as metal expands and contracts in cold, Metro says.

Reagan National Airport has seen a 50-degree swing in temperatures over the last few days as temperatures have gone from a high of 59 degrees on Monday to a low of 9 degrees on Wednesday, Metro says.

Most rail breaks are detected automatically by Metro’s signal system.

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