A MAMMOTH BRIDGE.

Evening Star, Issue 10401, 24 August 1897, Page 3

A MAMMOTH BRIDGE.

Chicago is to have the largest swing bridge in the world—a structure that will dwarf into insignificance all bridges of similar design, the size of which has been a matter for extended comment among engineers of international fame. It will be a fitting companion work in immensity to the monster skyscrapers and other architectural enterprises which have placed Chicago in the front rank as a city of wonderful development in material improvements, mammoth in size and unequalled in boldness of conception. This bridge will be long enough to span a full sized city block. It will be fitted with eight sets of railway tracks, and will be strong enough to sustain at one 'time eight loaded trains carrying a combined weight of 16,000,000 pounds, which is equivalent to tho maximum capacity of 500 modern freight cars. Nothing approaching it in s ; ze has ever been attempted in bridge construction on the swing plan. The largest structure of this kind now in use is the celebrated Harlem River railway bridge n New York, which has been noted the as a masterpiece of mechanical engineering. The Harlem bridge has only four tracks—just one-half the traffic facilities of the one on which Chicago engineers and contractors have just begun work. The cost, complete, of this giant structure, with motive power and expenses of maintenance, will be close on £200,000. It will take 7,000,000 pounds of steel to build this bridge. The cross girders will weigh ninety tons each. Its sustaining power will be 40.000 pounds to the lineal fopt. Electricity will be used as the motive power, the entire structure turning on pulleys like those used in the city bridges, but considerably larger in size. The work of construction will keep a large force of mechanics busy for twelve months.—‘ Tribune.’