Montgomery County planners today endorsed building a light rail system along the proposed east-west Purple Line and recommended running the trains mostly above ground and next to the Capital Crescent Trail, a heavily used hiker-biker route.
I don't really know these communities so don't have an opinion about whether this is awesome or not. But in general the awesomeness of such projects depends on the degree to which land use and development patterns around the corridor/stations are allowed to change.
More info here.