The children are exploring an old railway tunnel when Phyllis becomes frightened by the approaching darkness. She wants to leave but the others convince her to stay. They hear a rumbling sound on the tracks growing louder, realizing it's an incoming train. Peter leads them to a manhole recess to take shelter as the train roars through the tunnel, described as a dragon with fiery eyes. Phyllis stumbles in the dark but they all make it safely into the recess. The train passes by loudly and dangerously before silence returns to the tunnel.