"Northend Electrification Project" . "electrification project between New Haven and Boston" . "Amtrak's 60 Hz traction power system" . "Amtrak's 60 Hz traction power system" . . . . . . . . . . . "60 Hz traction power system" . . . "electrifying the route" . . "25 kV 60 Hz AC" . "electrification" . "25 kV AC at 60 Hz" . . "25 kV, 60 Hz" . "extends electric train operation" . "25 kV, 60 Hz AC" . "Amtrak's 60 Hz traction power system" . "Amtrak upgraded the track" . . "Amtrak" .