Engineering Wonders of the World
Volume I

BY A NEW YORK ENGINEER. This Article tells how Engineers have solved to a large extent the Traffic Problems created by the fact that wide expanses of water separate the main business centre of New York from the neighbouring shores of Long Island and New Jersey. TWO cities are pre-eminent as centres of subaqueous tunnelling—London and New York. The Thames, and the much broader Hudson and East Rivers, which split up their respective Sub-River cjties, furnished the oppor- Tunnels in |un^y whiie the demand for New York, transit facilities created the necessity, for river tunnels. Underground railways—those great modern instruments of urban rapid transit—supplied the chief stimulus for tunnels in both cities ; for, while streets can more easily cross a river by way of bridges, and surface or ele- vated railways are still better adapted to bridge crossings, an underground railway will generally find it easier to dip into a tunnel than to rise up to a bridge. Of the seven- teen river tunnels in New York city, all but two were built for railway use. London is the birthplace of shield tunnel- ling, and British engineers have been fore- most in developing the art. New York, however, has presented by far the most diffi- cult problems in subaqueous tunnelling, and the tubes under the Hudson and East Rivers rank among man’s greatest triumphs of tunnel construction. The seamed and faulted rock of the East River, and the soft, flowing mud which forms the bed of the Hudson to a great depth, are formidable obstacles, over- come only by the exercise of admirable courage and skill joined with never-ending patience. Add to this the fact that the New York work has all been done in very recent years, and we may fairly conclude that in order to learn of the wonders of compressed-air shield tunnelling we must study the tunnels of New York. A good notion of the location of the tun- nels may be obtained from the enlarged sketch-map of the lower part of Manhattan