The size of the U.S. makes reliance on trains difficult even with significant investment. It would be nice if they were a more reasonable alternative to air travel to more places and that seems reasonable to accomplish. I took a train from New York to Florida once. I don't think replacing cars with trains is practical though. Streetcars are fine but I don't really think they are necessarily superior to busses and most cities, even relatively small ones, have those. Bus routes are easier to change and expand that streetcar routes.