Engineering Wonders of the World
Volume I

THE UNDERGROUND RAILWAYS OF CHICAGO. ' 365 freight daily, Phila- and Boston about tons each, Chicago tons. The under- railways do not expect to move all . Direct Connection with Warehouses. is now being pushed but the authorities the merchants and advantages of the Removing Excavated Material. street “ head houses ” were erected. Here the loaded cars from the tunnel beneath were brought up through vertical shafts, and their contents were dumped into wagons to be transported to the lake front. This carting of the material through the streets of the city was done at night only. The dirt was utilized for reclaiming nineteen acres from the lake and adding them to the city’s park, without one cent of expense to the park authorities. The Tunnel Company now run cars to the surface at the “ dump ” by means of an inclined railway connecting with their system. Wherever a big building has been erected in Chicago during the past two years the subway has been employed to haul away the material excavated from the foundations. This is accom- plished by simply running up from the tunnel to the ex- cavation a shaft about three feet in diameter. The workmen wheel their barrows of soil to the yawning mouth and empty them into it. As these shafts make an angle of about 45 degrees with the horizontal, gravity carries the débris to the bottom, where it falls into a waiting car. One car filled, another is moved under the mouth of the chute, and when a train has been made up an electric locomotive hauls it away to the lake front. By this method the subway has moved from the basement of one building alone 2,100 cubic yards of material in twenty- four hours. The best record by teams in the same time is 420 cubic yards, and to do this even it was necessary for the contractors to stop their overhead work entirely. As already stated, when the system was declared open in November 1904, 20 miles of lines had been laid. By September last the mileage had increased to just over 60. Naturally, the greatest revenue from the operation of the tunnels comes from the trans- portation of freight. There is more freight hauled through the streets of Chicago than through those of any other city of America. New York hauls about 75,000 tons of delphia 65,000 100,000 ground this freight, but are prepared to take one- third or more of it if they can get it. This branch of the business forward energetically, have had to educate manufacturers to the subways. First of all they offered to install, free of charge, in any of the large ware- houses and stores along their route, special shafts and elevators, to connect these estab- lishments with the subterranean railway. The first fifty installed cost £200,000. But these houses find them invaluable. The cars of the underground system bring goods direct from the railway depots to the basement of the buildings, whence elevators raise them to the desired floor. Of course, this direct connec- tion between tunnel and warehouse is not always possible, so the railway authorities have built central depots at various places throughout the city, so that a shipper is not obliged to haul his merchandise more than a few hundred yards. Two years ago the subway officials secured from the postal authorities a contract for the transportation of the mails. This con- tract was obtained only by convincing the powers that be against their will of the ad- vantages offered by the new system. The main post office Chicago is the heaviest edifice in the city, and its enormous weight is supported on piles driven down to bedrock. When the engineer first approached the postal officials with a pro- position to connect the building with the tunnel system, so that the mails might be Carrying the Mails. building in