QUOTE(EdFindlay @ May 20 2012, 09:40 PM)

If you remember the Amtrak Cape Codder, then you know the proposed route south of middleborough.
I never rode the Cape Codder, but I know that its route left the NEC in Attleboro, MA and ran east through Taunton to a point adjacent to the Middleboro/Lakeville station (then not in use as the "T" was still years away from restoring Old Colony service). It then ran parallel to I-495 and MA-25 to Bourne, and then over the bridge onto Cape Cod - finally running parallel to MA-28 down to Hyannis.
The Cape Codder (which interestingly used Metroliner equipment) ran north on Fridays only from Washington to New York in a regular weekday Metroliner hourly slot, but then continued east of New York to New Haven, where it changed engines, and then continued up to Attleboro before branching off on the above route. The equipment made a shuttle round trip on Saturdays Hyannis to Providence and Providence to Hyannis (connecting to or from corridor trains at PVD). Then on Sundays it left Hyannis and ran to New Haven, changed to electric engine, and terminated in New York (not Washington). In its later years before extinction, it became a Boston-oriented train, though I don't recall whether it went via Attleboro or if the tracks were passable on what is now the Middleboro commuter line for it to take the more direct Old Colony route into Boston (or Braintree for Red Line transfer)
The idea for this service sounds similar in days of operation, only the through trains Friday and Sunday would run through to/from Boston, and the Saturday short turns would be at Middleboro to connect with existing commuter service.