Unless the mainline between Braintree is double tracked to Boston, there is no way that the "Middleboro/Lakeville" route could become reality.
Right now with the Greenbush Line now sharing the mainline to Boston with the Kingston/Plymouth and Middleboro/Lakeville Lines, it is at maximum capacity. In fact, the K/P and M/L trains are now experiencing late arrivals for the firt-time due to the addition of the Greenbush trains. Commuters on those lines that opened in 1997 are not happy.
My friend, John Brennan, former Director of Commuter Rail for the MBTA in the 1990s, asked his Engineering Department to do an estimate of double-tracking the track from Braintree to Boston. Halfway from Braintree the cost was estimated at about one hundred million dollars;...the estimate was then shelved. Remember, the extension of the T's heavy rail rapid transit "Red" line to Quincy, and later to Braintre, used up the old New Haven RR RofW. Fortunately, one track was left in for freight service;...if this had not been done, we probably not have the restored three "legs" of the Old Colony Service on the South Shore.
The existing roadbed of the Stoughton-Easton-Taunton route is the only sensible and feasible way to go. The critters in the Hockamock Swamp existeted for over a hundred years with steam and diesel engines passing through the Swamp with no problemas at all. This is one of the "phoney" issues the anti-rail people are in a snit about. Basically it's NIMBYISM, period! (can you say "Greenbush?)
There is a huge market for rail just from the Easton, Raynham and Taunton alone;...Freetown, Berkely, New Bedford and Fall River are also large population centers for use of commuter rail. The Stoughton route was studied at the cost of millions of dollars and was selected for the construction of the rail route in 2003. It met all environmental standards. But the project was never funded by the wimps on Beacon Hill.....plop!
Now, three years later, we are starting the whole process all over again at a cost of more millions of dollars! This is totally outrageous!
Now, who knows what will happen!