Congratulations, you've slayed a strawman. It's pretty clear both the OP and myself were talking about passenger trains, which in the US can't be operated at a profit.
It's apples to oranges. The US rail network is optimized to solve another problem. The evidence I've seen indicates that US freight transport by rail is among the most efficient in the world. It's hard to adduce it as an example of technical failure.
Even on your terms of debate I think you need to cite evidence of overall profitability of passenger trains in other countries. Deutsche Bahn (DB) makes some money but depends on substantial subsidies from the German government. [0] Wikipedia shows that most passenger rail seems to be heavily subsidized, though interestingly not Japan. [1]
