For the purposes of analyzing America's rail system with its highway system, consider the following graphics:
Eisenhower Interstate Highway System, completed in the early 1990s, more or less as envisioned in 1943:
Double-track rail system in U.S., as of 2006 (Trains Magazine):
As you can see, the U.S. is far behind in its development of a double-track network, the only configuration that allows for relatively free-flowing, nonstop freight and passenger train traffic. Until this condition is remedied, a passenger rail system worth having is out of the question.
These two graphics also demonstrate the power of tax money when diverted towards a single purpose (road graphic), and that of the limited capability of the private sector (rail map).