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Page:Popular Science Monthly Volume 90.djvu/95

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The New Tunneling Machine

���Above: The fourteen hammers are ar- ranged on a longitudinal axis and are fitted with chisels which cut into the solid rock in great concentric circles

��The carriage of the machine consists of a two-wheel main truck at the rear and a guide truck at the front. The wheels rest on a light track of standard gage


�� �