There isn't a train to from Boston to Newport, there is only bus service. You can take the Peter Pan bus from South Station to Newport or take an Amtrak train from South Station to Providence or Kingston. If you take a train to Providence there should be a bus that runs from Providence to Newport through the RIPTA.
Kingston, RI is the closest station to Newport. From there van/car service is available to Newport. Kingston is on the Northeast Corridor.
You have to specify which Newport you are asking about.
Boston harbor
Newport, NH
It would take about an hour and a half to drive from Newport, Rhode Island and Boston, Massachusetts. There is approximately 71 miles between the two locations.
Newport News has an Amtrak station at 9304 Warwick Blvd. It is on the Northeast Corridor.
About 70 miles.
Peterpan Busline.
71 miles
northeast
Boston Road Train Station was created in 1964.
Boston Road Train Station ended in 2010.