Railfan/Trailfans at the informal rail-w-trail in Belmont
This is a question that we get asked--often. We don't know. We do know that many studies have been done to research that question and they all say the same answer. It doesn't really work as a railroad anymore. Not for freight and not for passenger operations--including commuter rail. The report below is the most recent look at the question for commuter rail.
We know that if the railroad was needed and viable, it could come back. We also know that the trail could be alongside [rail-w-trail] in most of the length where commuter rail would come back. In fact there are over 80 rail-w-trail projects now in operation around the U.S. and by the time this corridor were needed for rail operations, there will be many more dual use corridors in operation--including perhaps a few more operated where the MBTA runs heavy rail [commuter rail] or light rail [trolley].
Here's the official MBTA study that looked at restoring rail service on this corridor