FREEPORT, Maine, June 27 -- The National Railroad Passenger Corporation (Amtrak) issued the following news: * * * Tech added to over 100 miles of track between Haverhill, Mass. and Brunswick, Maine * * * Amtrak and CSX, in partnership with the Northern New England Passenger Rail Authority (NNEPRA), will install Positive Train Control (PTC), the technology capable of automatically controlling train speeds and movements, on more than 100 miles of track between Haverhill, Mass. and Brunswick, M  more