In an effort to keep local officials thinking about the proposed Purple Line, local transit activist group Action Committee for Transit is organizing a flash mob in downtown Silver Spring Thursday evening.

The group plans to meet at Colesville Road and Wayne Avenue at 5 p.m. Dressed in purple to show their support for the Purple Line — the light rail planned to run from Bethesda east to New Carrollton — the group will be doing a three-minute dance while holding signs, said ACT President Tina Slater.