WMATA's Rider's Advisory Council's Rail subcommittee will hear a presentation (PDF) on realigning the Blue/Yellow line trains this Wednesday at 6:30 p.m (PDF). This similar to the same idea circulated earlier this year about diverting some of the eastbound Blue line trains toward the Yellow line to relieve capacity at the Rosslyn tunnel. They're proposing calling the new service (from Franconia/Springfield to Greenbelt) the "Brown Line" (see page 7 of the presentation).
This change may result in blue line service reduction to every 12 minutes during rush hour, and an increase in the number of orange line trains leaving Vienna during rush hour. See the presentation for more details.