I'm somewhat puzzled by the original comments. Just what are you getting at? Mr Robl sums up high speed very well. High speed trains throughout the World are all extremely successfull. Not sure what you're implying by the reference to grades. ALL high speed electric lines have no problems with grades - indeed this is the beauty of high speed electrification. Modern elctric units and control systems take it all in their stride & reduce considerably the construction costs. I'm puzzled by reference to grade crossings. What do you expect on a high speed line?? Flashing lights & barriers? Just what are you saying?
The Japenese network is not finished, simply because it is so successfull it keeps expanding. I spent a holiday this year using Shinkansen and it is truely breathtaking.
The biggest handicap to high speed rail in the USA is the US attititude to public transport versus car. I really don't think you have the will, nor the way.