Upon closer exam, the silver arch bridge might be Boylston St. which runs along the buildings along the right side of the photo and crosses the tracks using the silver bridge. The Massachusetts Ave. bridge is behind the Boylston St. bridge but is not visible in this photo. New Haven tracks are to the left of the mainline. NYC coach yard is to the right of the mainline. Of course this entire area was replaced by the Prudential Center with only two through tracks to South Station.

This must be a view facing west due to the shadows South Station is ahead of the train. That is Massachusetts Ave. bridge to the rear. So the train is either pulling into or is backing out of South Station, which is a mile or so ahead of the train.