A counterargument is that both highways and trains benefit from economies of scale. If you gave highways 1.8 billion in subsidies and Amtrak 75 billion, I would expect the miles per dollar of subsidy to look substantially better for Amtrak than they do now, and worse for roads.
That said, I suspect we overinvest in both subsidies because of romantic ideas and status quo bias.
That said, I suspect we overinvest in both subsidies because of romantic ideas and status quo bias.