JimBoylan wrote: Now that the State of Massachusetts owns West to Worcester, a Boston South Station to Hoosac Tunnel trip could be possible, without CSXT's permission. The Providence and Worcester might also cooperate for a different routing.
Hoosac Tunnel is on the Boston & Maine, now the "Pan Am Southern", not on CSX's B&A. Pan Am is an Amtrak operator that recently hosted a private car fantrip on the West End, so my guess is that if Amtrak wanted to run to the Berkshires out of North Station, that could happen.
Amtrak has operating rights over the B&A so they could presumably run a Boston-Berkshires excursion (to Pittsfield, likely) on their own. This has happened in the past under the sponsorship of the Mass Bay Railroad Enthusiasts.
Providence & Worcester does run occasional excursions on its line using its own equipment.