As Danger Man says, Look at Europe and you will see what it could be. I lived in Europe for five years and traveled extensively on the rail system. It is a fine system with comfort, frequency and many destinations. People use it extensively, but it is not profitable. It is, however, strongly supported by their governments - in development, capital outlays and operating subsidies. Our country is very far behind the curve on rail transportation. Our government threatens to bankrupt Amtrak every time we go through a budget cycle and they nickel-dime & try to micromanage Amtrak.
Amtrak is a Crown Jewel asset to our country, we just don't have enough intelligent, caring and forward looking politicians to recognise its value!!