Forgive me for maybe being a bit naive on how passanger rail networks work, but all this scheming between MassDOT, CSX, Nashua etc. Seems to be a recipe for disaser. If they all really do decide to run trains into NH without the NH state government behind it you would suddenly have a bunch of mad legislators that already didn't like passenger rail. I could see them coming up with all kinds of laws and regulations to gum up the works. Large fees for trains crossing the border or sitting at stations or layover yards in the name of "environmental protection", requiring outrageous "safety" measures on trains or at stations or layover yards that make them infeasible, legsliating taxes on train fares making them outrageously expensive. An angry politician, particularly an angry New Hampshire politician, can make life hell.
Am I missing something? I am not an expert in any way about interstate rail but I imaging you need the state on your side or they will tax and legsliate you into oblivion.