I was mulling over how to defend light rail against heavy rail when the impressive image of one of those big Kawasaki South Shore cars rolling down a street in Michigan City, Indiana came to mind. If you dispense with the blankety-blank third rail and broad gauge you can run any weight of vehicle you want pretty much anywhere. Even a doodlebug.

I realize that grade separation is a wonderful thing and to be achieved wherever possible but being able to take advantage of the public's enormous investment in roads and streets can be the difference between having a rail transit system and not having one in our lifetime. LA presents a pretty good example of that right now.