First, sorry for the big gap in posting. A summer job and a finger splint can do that.
For some reason, intercity transit is more interesting to me than commuter rail. Maybe it's the lower operating subsidy, maybe it's the chance to expand people's car free worlds by hundreds of miles, not dozens, or maybe it's just that passing costs on to others is easier due to Federal funding, I have no idea.
This post is going to be dedicated to the concept of intercity rail in New England, with a brief overview of each of the non-MA states prospects, followed by a discussion of how we can link those ideas together into a functioning network. For reasons of simplicity and brevity, I will not discuss any commuter rail initiatives here.
Currently served by the Northeast corridor, Connecticut has only a few simple improvements to make. All of its major cities but Hartford have fast, electrified rail service to NYC and BOS*, and all of those but New London have amazingly frequent commuter service to NYC. Unfortunately, Hartford gets the short end of the coupler. They get 4 trains per day to New Haven, where they must connect to an NER for trips to New York or Boston. They also get one Northeast regional southbound, which terminates in Springfield. Therefore, the Hartford-Boston travel pattern is extremely poorly served. They would be well served by the existing "Knowledge Corridor" plan for multiple frequencies New Haven-Brattleborough, with other frequencies routed on the "inland route," a Mass plan for detouring some Northeast Regionals to server Hartford-Springfield-Worcester. Since the ball is in MA's court for both improvements, Connecticut just has to keep focusing on State of Good Repair for the NEC.
Rhode Island is currently in the best shape of any state, having fast, frequent service to both NYC and Boston. Of course, it is helped by having only one major city. There is a tenuous proposal for hybrid commuter/intercity service Providence-Woonsocket-Worchester, but it's chances of actually happening are slim and the trip would always be a distant third from a PVD-XXX market size perspective. Excepting normal NEC improvements (more frequency, state of good repair, longer trains, etc.) Rhode Island is in a good place, at least for the near term.
Maine, Vermont, and New Hampshire, are in a slightly different position from the southern New England states. They all have relatively rudimentary service, extremely so for New Hampshire, and, due to their smaller and sparser cities must rely on Boston traffic to "keep the trains full". This means the trains that run here need to run through Mass for performance reasons, creating a great opportunity for well designed connections.
With that said, Maine currently operates a multiple frequency, well designed intercity train, the Downeaster. As its name implies, it swerves Boston North Station-Portland, acting both as a commuter route and as an intercity service. However, the fact that it terminates at North Station presents a problem: it connects with no other intercity trains! The extremely valuable business of taking businesses travelers from the Acela and spreading them out across the Northeast is completely unavailable. Therefore, the service must stand on its own. It should do so by speeding up its primary market, BON-PDX, before it extends service to Augusta or Rockland or anything else. As long as it has a strong trunk the line will do fine, but stretch it between to many small cities and the financial performance will start to tank. Beyond that, Maine just doesn't have the density to make intercity rail work.
*BOS: Boston South Station
BON: Boston North Station