Paul Krugman blogs about trains:
Some of the comments on my various pro-train posts have been along the lines of “Oh yeah, try taking the train to Los Angeles.” But that, of course, misses the point.
I endorse Krugman’s analysis, but in some ways I think the fact that you can’t get to LA on a train actually is the point. You can’t take the train from New York to Los Angeles. You can’t drive from New York to Los Angeles. You need an airplane. But LaGuardia Airport has limited runway capacity and many daily flights to Boston. Clearly, though, you can take a train from New York to Boston. So money spent on improving the speed and passenger capacity of NYC-Boston train links is, among other things, a way to improve New York’s air links to the West Coast.
Now a separate question is whether there’s any feasible way to actually do this in a country that doesn’t have a French (or Chinese) level of central political authority empowered to build straight tracks through people’s suburban backyards. The answer seems to be “no,” but the potential gains from greater rail capacity in the northeast are large and would (via airplanes) spill over into the rest of the country.