Engineering Wonders of the World
Volume I

THE BRIDGES OF NEW YORK CITY. 275 Fig. 27.—WASHINGTON BRIDGE, OVER THE HARLEM RIVER, NEW YORK. (Photo, Geo. P. Hall.) Fig. 28.—THE SUBWAY ARCH BRIDGE OVER MAN- HATTAN VALLEY, BROADWAY. Fig. 29.—THE SUBWAY ARCH BEING ERECTED ON THE CANTILEVER PRINCIPLE, WITHOUT FALSE- WORK SUPPORT. Fig. 30.—WALNUT LANE BRIDGE, PHILADELPHIA. This photograph shows the centering shifted from under one half of the bridge ready for the construction of the second and parallel half. span, designed to cross Spuvten Duyvil Creek at the northerly end of Manhattan Island. Its construction will be a prodigious task for the builder, though the designers feel con- fident of success. No better idea can be formed of its size than by looking at Fig. 30, a view during construction of one of the largest existing concrete arches, the Walnut Lane Bridge in Philadelphia (span 232 feet), and noting that the Henry Hudson arch would have a span three times as great. The third of the proposed leviathan bridges is a 3,000-foot suspension span across the Hudson River at 59th Street, almost twice as long as that of any one of the East River suspension bridges. Although engineers con- sider that it offers easier constructive problems than the Henry Hudson Bridge, it is rather visionary, for the reason that it would be