The rebuilding of a streetcar line in downtown Los Angeles is the type of old-school solution that will help remake the area into a modern city.
While some of the streetcar critics' arguments have merit, there is no chance people will park their cars and choose public transportation if there is not a convenient alternative. The streetcar line would provide that option.
This is a terrible idea. Rail lines mess up traffic and are expensive to lay and maintain. Overhead wires are ugly (take it from someone who had to deal with the old lines). Try faux-streetcar electric buses if you want to decorate and eliminate exhaust.