I agree (almost*) entirely with Paul Krugman about the second rail tunnel from New Jersey to New York:
Many reports that Chris Christie is about to scuttle the second rail tunnel under the Hudson. If so, it's arguably the worst policy decision ever made by the government of New Jersey -- and that's saying a lot.
The story seems to be that Christie wants to divert the funds to road and bridge repair; but in so doing he would (a) lose huge matching funds from the Port Authority and the Feds (b) delay indefinitely a project NJ needs desperately ASAP. He could avoid these consequences by raising gasoline taxes. But no, taxes must never be raised, no matter what the tradeoffs.
And it's a social bad too: now is very much the time when we should be ramping up infrastructure spending, not cutting it.
Whatever you think of rail projects elsewhere, they work in the Northeast. In the case of the New York tri-state area, that's too mild; the fact is, the city could't work without rail. There's simply no way to cram more people onto the island of Manhattan without mass transit. Not only are the three major entry points from New Jersey thoroughly bottlenecked, but also, the streets are so congested that bringing more cars in would be disastrous. And since Manhattan already has roads about everywhere you can put one, the only answer is rail.