Page:Popular Science Monthly Volume 88.djvu/561

 Popular Science Monthly

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��The "Hump" cut passed through the very heart of the City of Pittsburgh The work took eighteen months

����city and to the base- ments of the large office buildings.

The particular conduit line leading into the "Hump" district which had to be rebuilt con- tained seventy ducts where it left the cen- tral vault, thence sixty ducts in Straw- berry Alley, and branched out via Grant Street, 01i\'er Avenue, Diamond Street and Tunnel Street. It was necessary rebuild the cable vault question. Where the seventy-duct line was lo- cated on Pentland (formerly Fountain) Street, the "Hump" cut was only a few feet down. The new grade was cleared by removing thirty-five ducts off the top of the seventy-duct line and building them down on the side, thus making a

��Cables were placed in a plank box, shown at the right. The ditch is twenty-two feet deep, cut mostly through blue rock and limestone by means of steam drills and dynamite

the wdrk was eighteen months, costing the telephone company about $75,000.00. This is the largest jol.) of the kind ever attempted and successfully accom- plished. At the rear of the telephone company's main exchange, located at 7lh Avenue and Grant Boulevard, there is a central cable vault or underground room about eighteen feet square, extending out under the street, from which radiate in various directions the underground con- duits leading to different parts of the

���Cables systematically arranged and hung in the trench preparatory to being low- ered into the solit ducts

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