Engineering Wonders of the World
Volume I

■ 348 ENGINEERING WONDERS OF THE WORLD. attacked, there were many local tasks of exceptional character that taxed the daring and skill of the builders. At several points the Subway passes under the columns of the elevated railways. To be able to excavate underneath, it was necessary- plot of ground on which the Times was pre- paring to erect a skyscraper office building. The building Through a i x n. , • . , ,, Skyscraper. has two cellar stories below the Subway floor-level. The Subway floor here was built on columns which pass down through Fig. 8.—TRUSS SUPPORTS OF CAR TRACKS ON BROADWAY. edges were driven between to support the columns on timber trestles set in pits reaching down to the Subway floor-level. Steel girders were Supporting pIaced across these trestles, and Elevated Railway Columns. the girders and brackets at- tached to the columns to transfer the latter’s load from the old to the temporary foundation. Later, when the Sub- way structure was completed, new concrete piers were built on its roof, under the columns. The temporary supports in all cases bore the load and concussion of the fast railway traffic these cellars to foundations independent of the building. The steel frames of Subway and building (Fig. 10) were erected simultaneously, but are entirely independent. Half a mile east, at the Belmont Hotel, the same problem was handled in almost the same manner. At 59th Street the tall stone shaft of the Columbus Monument stands partly over the Subway. Specially careful work was necessary in undermin- ing the heavy stone mass, digging under • V .-nn . A a Monument, weighing over 700 tons. A small tunnel was first dug under the middle above without the slightest accident. of the foundation, and a wall built down to At 42nd Street and Broadway, a sharp curve, the structure had to cut through a rock, to furnish a reliable permanent sup- port. Then the edge under which the Subway