AlanB

First just to be clear, Shoreline East has nothing to do with Metro North, beyond the fact that they run a few trains down to Stamford on MN tracks. But Metro North is operated by the MTA of NY with help financial from the State of CT for the portion that runs within the state. Shoreline East is run by Amtrak for the State of CT.

That said, Shoreline East isn't affected by the bridge closure at all, since most of their trains terminate in OSB as mentioned by the_traveler. Two trains per day, IIRC, terminate in New London, the very last stop before the bridge in question.

Now, because Amtrak also plans to do a track maintenance blitz during the shutdown of the corridor, it is possible that Shoreline East may encounter some delays due to single tracking and slow orders in areas where people are working on the tracks. But regardless, the SE trains will run.