Someone sneezed. I looked behind me. Nothing. No, it wasn’t a sneeze . . . it was a train—a six o’clock freight train pulling through the train shed just west of the tunnel. Now came a mournful whistle blow, followed by two more. Ordinarily, I love the sound of a train, but this was distracting. What should I do? I crept several more paces inside the hollow tube, hoping to recognize the person at the other end. The man had definitely moved closer but I couldn’t identify him . . .