From WMATA's website:
Metro announces weekend Red Line single tracking
This weekend, Metro will continue to do maintenance work on the Red Line in preparation for the opening of the New York Avenue-Florida Avenue-Gallaudet U Metrorail station. During this work period, customers' trips will take 10-15 minutes longer than usual.
Please note the following schedule for this weekend:
• Red Line - On Saturday, August 28, and Sunday, August 29, from opening (7 a.m.) to 7 p.m., trains will share one track between Rhode Island Avenue and Judiciary Square. [To help expedite the flow of rail travel, all Red Line trains which normally operate between Grosvenor-Strathmore and Silver Spring, will terminate at Judiciary Square and return to Grosvenor-Strathmore.]
To perform this work, Metro must single-track trains - operate trains traveling in opposite directions alternately on the same track. On the Red Line between Rhode Island Avenue and Judiciary Square, Metro personnel will continue to install new communications cables and wayside track equipment for the New York Avenue-Florida Avenue-Gallaudet U Metrorail station scheduled to open at the end of this year.
For more information on traveling by Metrorail or Metrobus, customers may call (202) 637-7000, TTY at (202) 638-3780, or visit Metro's Web site at http://www.metroopensdoors.com/ .