THE TRAIN TUNNEL RAN FOR 50 CITY BLOCKS, NEARLY THREE miles, under Manhattan streets and parkland. It stretched along the island’s far west side, near the Hudson River, from West 72nd Street, underneath Riverside Park, all the way to West Harlem. It was one of those rare places that made you feel both inside and utterly outside the city—as if, for a few moments, you could convince yourself that you’d fled the chaos and noise of New York without ever leaving.
The first time I walked deep into the tunnel, I felt myself steadily, step by step, becoming wrapped in darkness. It was autumn, 1995, and as the sunlight from the southern entrance faded, I could feel my pupils dilating to capture the available light, allowing me to glimpse the…