DDOT initially conceived the Anacostia light rail as a starter system for a network of light rail lines throughout DC. Anacostia was chosen to be first as it would be connected to the rail yard and be relatively inexpensive to build. This was contingent on obtaining CSX's right-of-way to build a (relatively) high-speed connection through Anacostia between the Anacostia and Minnesota Ave. stations. The deal fell through, so DDOT is now reduced to trying to build a light rail line in Anacostia to, well, perhaps show that it can be done. As Greater Greater Washington has pointed out, the latest incarnation will continue an all-too-short (and low speed) distance on Anacostia's streets and maybe will be extended to the 11th St. Bridge. After that, there is simply no plan.
DDOT also assumed away the problem of the ban on overhead wires. Not every light rail line can go on abandoned railroad tracks. In fact, one of the illustrations shows overhead lines on a street. Let's face it, the overhead line ban is not going away. Moreover, given improvements in power storage technology, it may be possible to avoid them completely by having quick charges from short overhead lines integrated into stations.
So, DDOT has to go back to the drawing board. First, it has to find a way to get the CSX right-of-way. Eminent domain is a possibility that hasn't been tried. This may be difficult, as railroads are generally accorded strong property rights. You can't do a lot of things to railroads that you can do to other properties. Still, the line is abandoned, which is the argument that DC will have to use. Second, DC has to solve the overhead wire problem. By doing so, it can reduce construction costs and set an example for other cities to emulate. The Anacostia LRT can be used as a test bed.