The following three photos show the ventilation shafts cut into the roof of the tunnel to allow fresh air into the tunnel, and dirty air (from the steam locomotives) out. There were three of these holes along the roof of the tunnel, that led to smokestack-like structures on street level. Note in particular how thick the brick arch is at the top of the tunnel. In the first photo below, Atlantic Avenue is directly above the planks that now cover these three shafts.

When the tunnel was closed, the three smokestack-like structures on street level were knocked down, and the debris fell through to the tunnel. Their debris still litters the floor of the tunnel, below each of the three shafts.

During World War I, the FBI suspected that the Germans were making munitions down in the tunnel. To prove their theory, they broke through a basement along Atlantic Avenue to gain access to the Tunnel. Below is where they entered. They found nothing, but left a message on the wall for future generations: "... Lynch Put First Electric Light in the ..." The message is dated 3-11-16 (near the arrow).

Thanks to Steve (left) for scanning the pictures. Cliff is at right.