These are absolutely incredible photos.
First up, a Green Line (but orange-colored) train leaves North Station.
Nothing in this photo exists, any longer. The Garden is gone, the Hotel Edison is gone, and the elevated subway is gone. I think several of those buildings to the left are gone, too.
Second up, an Orange Line train at the corner of Washington Street and Massachusetts Avenue, in the South End.
The Orange Line used to be an elevated train, from Dudley Square to Chinatown, where it entered a tunnel, then came out the other side, at North Station.
In this photo you can see Minot Hall, back behind the train, (and the Hancock Tower, further off, obviously). You can see the Hotel Alexandria, closer-up, looking not much worse than it does today, thirty years later. Unfortunately, “Uncle Ted’s Money To Loan” is gone.
More photos of Boston’s public transportation system (past and current day): NYC Subway website