Few residents of Concord ever discuss the medium-security men’s prison that is part of our community.  Its presence here is quite incongruous with virtually everything else. I have been told that it is a significant contributor to our tax base and the reason we can afford to leave so much of the town’s land undeveloped.  I took time this morning to explore a new section of the Bruce Freeman Rail Trail which goes right past the prison and ends (current construction phase) a short distance later. I continued on along the undeveloped part of the train corridor over Nashoba Brook and across Route 2 until further progress was blocked by water and/or vegetation..