. Manual for railroad engineers and engineering students : containing the rules and tables needed for the location, construction, and equipment of railroads as built in the United States . Fig- 39- each end to the centre. Shaft No. 1 is 1498 feet from the west-ern end, and has a section of 6 X 6, and a depth of 215 No. 2 is 2183 feet from the western end, and has a sectionof 13 X 6, and a depth of 277 feet. These shafts were sunk forthe purpose of drainage, before the heading had been driventhrough from the west end. The West Shaft, 2447 feet fromthe western end, is 14 X 8 feet, and
. Manual for railroad engineers and engineering students : containing the rules and tables needed for the location, construction, and equipment of railroads as built in the United States . Fig- 39- each end to the centre. Shaft No. 1 is 1498 feet from the west-ern end, and has a section of 6 X 6, and a depth of 215 No. 2 is 2183 feet from the western end, and has a sectionof 13 X 6, and a depth of 277 feet. These shafts were sunk forthe purpose of drainage, before the heading had been driventhrough from the west end. The West Shaft, 2447 feet fromthe western end, is 14 X 8 feet, and 318 feet deep, and is theworking shaft where the material excavated eastward is hoisted. ROCKWORK AND TUNNELLING. 107 The Central Shaft, about midway between the ends of the tun-nel, is elliptical in section, 27 feet in diameter along the line oftheroad, 15 feet in diameter across the road, and 1030 feet Hoosac Mountain, on the line of the tunnel, rises to aheight of 2500 feet above the sea, and about 1800 feet above theroad. There is a double summit, and the central shaft is located. in the intermediate depression. The general character of therock at the eastern end, and at the central shaft, is mica slate,with quartz ; and at the West Shaft, a hard quartzite. Thefirst 2000 feet at the western end, being through a rapidly decom-posing material, required to be arched with brick. The headingshave been driven, and much of the enlarging done, by the ma-chine known as the Burleiirh Rock Drill. These drills are in io8 MANUAL FOR RAILROAD ENGINEERS. each heading mounted upon two carriages, standing side by side,with a space of about 6 feet between them. Each carriage sup-ports five drills ; but seldom more than four (eight in all) are inmotion at one time. They make from 180 to 260 strokes a min-ute, with a pressure of 60 pounds per inch. When a blast is to
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherbosto, bookyear1883
