NORTH BERGEN, N.J. (AP) — When the original train tunnel beneath the Hudson River connecting Manhattan to New Jersey was built more than a century ago, workers toiled with picks and shovels from each side until eventually meeting in the middle. A new tunnel, one of the largest U.S. mass transit projects in generations and which is expected to cost $16 billion, will take a decidedly modern approach. Giant drilling machines nearly the length of two football fields armed with cutters harder than diamonds will chew through dense rock. A crew of about 40 will oversee a conveyor system hauling out debris as well as equipment to install the tunnel’s curved concrete lining. “This is a fully automated, underground factory,” said James Starace, chief of program delivery for the Gateway Development Commission, a public agency formed by New York and New Jersey that’s undertaking the tunnel project.…