PAGE 5
The Sand-Hog
by
It was a new kind of thrill to me to go under the “air,” as the men called it. With an instinctive last look at the skyline of New York and the waves playing in the glad sunlight, we entered a rude construction elevator and dropped from the surface to the bottom of a deep shaft. It was like going down into a mine. There was the air-lock, studded with bolts, and looking just like a huge boiler, turned horizontally.
The heavy iron door swung shut with a bang as Paddy and Capps, followed by Kennedy and myself, crept into the air-lock. Paddy turned on a valve, and compressed air from the tunnel began to rush in with a hiss as of escaping steam. Pound after pound to the square inch the pressure slowly rose until I felt sure the drums of my ears would burst. Then the hissing noise began to dwindle down to a wheeze, and then it stopped all of a sudden. That meant that the air-pressure in the lock was the same as that in the tunnel. Paddy pushed open the door in the other end of the lock from that by which we had entered.
Along the bottom of the completed tube we followed Paddy and Capps. On we trudged, fanned by the moist breath of the tunnel. Every few feet an incandescent light gleamed in the misty darkness. After perhaps a hundred paces we had to duck down under a semicircular partition covering the upper half of the tube.
“What is that?” I shouted at Paddy, the nasal ring of my own voice startling me.
“Emergency curtain,” he shouted back.
Words were economised. Later, I learned that should the tunnel start to flood, the other half of the emergency curtain could be dropped so as to cut off the inrushing water.
Men passed, pushing little cars full of “muck” or sand taken out from before the “shield” – which is the head by which this mechanical mole advances under the river-bed. These men and others who do the shovelling are the “muckers.”
Pipes laid along the side of the tunnel conducted compressed air and fresh water, while electric light and telephone wires were strung all about. These and the tools and other things strewn along the tunnel obstructed the narrow passage to such an extent that we had to be careful in picking our way.
At last we reached the shield, and on hands and knees we crawled out into one of its compartments. Here we experienced for the first time the weird realisation that only the “air” stood between us and destruction from the tons and tons of sand and water overhead. At some points in the sand we could feel the air escaping, which appeared at the surface of the river overhead in bubbles, indicating to those passing in the river boats just how far each tunnel heading below had proceeded. When the loss of air became too great, I learned, scows would dump hundreds of tons of clay overhead to make an artificial river bed for the shield to stick its nose safely through, for if the river bed became too thin overhead the “air” would blow a hole in it.
Capps, it seemed to me, was unusually anxious to have the visit over. At any rate, while Kennedy and Paddy were still crawling about the shield, he stood aside, now and then giving the men an order and apparently forgetful of us.
My own curiosity was quickly satisfied, and I sat down on a pile of the segments out of which the successive rings of the tunnel were made. As I sat there waiting for Kennedy, I absently reached into my pocket and pulled out a cigarette and lighted it. It burned amazingly fast, as if it were made of tinder, the reason being the excess of oxygen in the compressed air. I was looking at it in astonishment, when suddenly I felt a blow on my hand. It was Capps.