There was, and still is, a quarry on the north side of the line in Blandford, and it has been in existence for many years. (Can't remember the name of the family that owns it.) I think it is primarily a crushed rock business.
If I recall correctly, the circa-1915 document that the New Haven published regarding the establishment of the line indicated that they planned to haul some freight on it. I don't know whether that ever happened during its brief existence.
None of this, of course, should be confused with the quarries on Chester & Becket branch of the B&A.
BTW: How navigable is the C&B roadbed, by foot, four-wheeler or car? Is there anything of interest left to see out there?