. Railroad structures and estimates . 180 Headint timbcreil15of Tunnel coiuplcto ISOMETRIC ELEVATION Fi;. 4. Isoiiutric S(Mtioi\ and Profilo. Uft Wall Platti Drift ■Earth- «J9 With the except ion of several hundred feet of clay and glacialdrift at each end, the drifts are in solid rock, which is expected tocontinue throughout the entire length. It is mainly slate, schistand quartzite. No timbering is required in the rock excavation. For the end portions, which arc in loose material and arc tim-bered, a concrete lining is required. This is 30 in. thick and 483 SECTIONS DOUBLE TRACK TUNNEL. 67 D
. Railroad structures and estimates . 180 Headint timbcreil15of Tunnel coiuplcto ISOMETRIC ELEVATION Fi;. 4. Isoiiutric S(Mtioi\ and Profilo. Uft Wall Platti Drift ■Earth- «J9 With the except ion of several hundred feet of clay and glacialdrift at each end, the drifts are in solid rock, which is expected tocontinue throughout the entire length. It is mainly slate, schistand quartzite. No timbering is required in the rock excavation. For the end portions, which arc in loose material and arc tim-bered, a concrete lining is required. This is 30 in. thick and 483 SECTIONS DOUBLE TRACK TUNNEL. 67 Double Track mBCTBTIS-rSrrr 1 1 ^ 1 < 0 ,1 ,k ^ig- -gx- ^ 7 < aim a
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Keywords: ., bookcentury1900, bookdecade1910, bookidrailroadstructur00orrouof
