Engineering Wonders of the World
Volume III

318 ENGINEERING WONDERS OF THE WORLD. tunnels were driven for the rails laid just above the blue clay, at a depth of 110 feet below the surface ; a large shaft containing five electric lifts was carried therefrom ; and over all, a commodious station was built suffi- ciently close to the street level to be ap- tings were removed, while the carvings and decorations were temporarily encased in wood. Four massive box girders of steel, each 53 feet long, were successively set on steel legs, resting on stanchions carried to suitable foun- dations. Each pair of girders was ranged ST. MARY WOOLNOTH—OUTSIDE GIRDER IN POSITION FOR SUPPORTING SOUTH WALL OF CHURCH, FACING KING WILLIAM STREET. proached on either side by a separate short flight of stairs. The achievement was truly described at the time as “ a marvel of engineering skill.” It involved the removal of the old foundations and the substitution of others which, while providing for all the necessary works of the railway, were sufficient to carry the immense superincumbent weight without causing the slightest movement in the architecture of the church itself. For the purposes of this task the floor, the organ, and all the internal fit- longitudinally alongside the old foundation piers and arches, and then saddled with smaller steel needle girders let crossways through the com- Supporting . P r the Column mon base of the tour groups ßases of columns carrying the roof. When the column bases were pierced for this purpose, it was discovered that the piers, in- stead of being sound Portland stone through and through, as was supposed, were merely shells of the material, varying in thickness from 6 to 9 inches, the interior being nothing