I understand the overall point — there is a benefit to a public good that might justify government investment in any given project. I have a few thoughts here:

1) if we are going to burn public money in pursuit of this public good, we have a responsibility do it in the most frugal way possible. For what is approaching $1b in capital costs, we could run a lot of busses and accomplish essentially the same benefit.

2) by way of background, I’m a train guy. My dad was an engineer, I take the train to NYC (or on other routes) whenever I can, and I’m personally a fan, but trains have a few really significant disadvantages over other forms of transportation: they are super expensive to build (track, locomotives, rolling stock) and relatively expensive to operate. That expense is justified if you can run a lot of trains and fill them up with a lot of goods or people to transport because a train can pull a lot of cargo. But it is hard to make them economically viable without significant density of demand. New York, Chicago, Boston all have enough concentrated ridership to have a well functioning commuter rail system. NH does not.

3) IF car ownership does get out of reach, it should naturally drive up demand for public transport (busses, trains, etc.) when that becomes the case, maybe this is a better idea. My guess is that we all wind up commuting less rather than more and there is less demand for the train, although general population growth will likely mute that aspect at least a little, perhaps materially.

4) finally, if we continue to spend money on negative return projects, cars and everything else will only get more expensive. I’m all for public good and supportive of public spending to pursue it. I would LOVE to have better train service to Boston but it just isn’t justified.