Engineering Wonders of the World
Volume I

THE RIVER TUNNELS it in tremendous volume. Attempts to seal the river bottom by dumping clay were largely futile, because the rock pile spread so far laterally. Nothing remained but to go through as best possible, timbering the face, packing it with hay, and supplying enough, compressed air to keep up the pressure in spite of the large leakage. For a period of several months therefore the shield work was a desperate fight against unusual odds, without a moment’s respite. But it went through. Mr. St. John Clarke was chief engineer for the company, Mr. W. B. Parsons consulting engineer, and Mr. Robert Shailer the engineer for the contractor in these tunnels. The Belmont tunnels had one great advan- tage over their neighbours—a half-submerged rock islet in the middle of the river, from OF NEW YORK CITY. 123 which work could be prosecuted as well as from the shore. This enabled them to be completed in unusually short time (July 1905 to September 1907). Indeed, though started after the neighbouring Pennsylvania East River tunnels, the Belmont tunnels were finished first. Speed is always an object in tunnelling. It pays to spend something extra per foot of tunnel and lessen the time of idle investment. But in this case there was an urgent additional reason for hurry, as the existence of the franchise depended on getting the work done before a fixed date. In this survey of New York’s river tunnels, one—the Harlem River Tunnel of the Subway —has been passed with silence, for the reason that the shield method was not employed, but instead a special method suited to its shallow depth and short length. Fig. 28.—A VERY SHARP CURVE OF 150 FEET RADIUS, HUDSON RIVER TUNNEL. {Photo, “The Scientific American.”)