I'll say this much. The new street car plan is better conceived than the big square that Mayor Barrett originally wanted. And, by way of full disclosure, it may well benefit me personally in that it may (sort of) connect my office to places that I frequently visit but can be a bit far to walk if weather and time are an issue. If the anticipated operational costs and ridership are correct, it might be financially justified.
But, given the history of mass transit projects, I doubt that they are. And when one adds in the capital costs (particularly the "free" federal contribution)it starts to look pretty sketchy. If we add in the apparent cost of relocating utilities, it's close to a white elephant. It's not clear whether the extensions would hurt or help cost effectiveness.
There are other problems as well. Will a downtown steetcar actually add to traffic congestion? Who will benefit? Not, I think low income folks but downtown professional and upscale residents.
This is always the problems with rail projects. Rail advocates seem to want to spend almost any amount of money on just about anything that runs on a fixed course in order to build "momentum." They hurt themselves in the process. By focusing on a train that did not work - the semi-express to that hub of civilization know as the Dane County Regional Airport - they arguably cost funding for one that does - the Hiawatha to downtown Chicago.
Rail can be a good idea but it is not always - and probably, given its limitations, not often - a good idea.