. The elements of railroad engineering . ere they are hoistedto the surface, or to the dump outside the tunnel. Whenthere is not sufficient grade to run the cars of themselves,mules are employed to haul them. A single track A, Fig. 448 (ordinarily of 3 feet gauge), islaid on the center line of the tunnel, with passing branchesat suitable intervals. At a distance of about 100 feet fromthe bench a simple switch is built, and two tracks C and Dlaid to the bench, which permit the loading of two cars atthe same time, and provide for shifting cars. On a levelwith the top of the bench, and directly o
. The elements of railroad engineering . ere they are hoistedto the surface, or to the dump outside the tunnel. Whenthere is not sufficient grade to run the cars of themselves,mules are employed to haul them. A single track A, Fig. 448 (ordinarily of 3 feet gauge), islaid on the center line of the tunnel, with passing branchesat suitable intervals. At a distance of about 100 feet fromthe bench a simple switch is built, and two tracks C and Dlaid to the bench, which permit the loading of two cars atthe same time, and provide for shifting cars. On a levelwith the top of the bench, and directly over the cars, a scaf-fold E is erected, and upon it a runway of planks F is laid, RAILROAD CONSTRUCTION. 953 extending from the scaffold to the heading. The headingmuck is loaded into barrows and wheeled on this runway tothe scaffold, and emptied directly into the cars. A simple and very effective bench scaffold is made ofwrought iron pipe supports and shown in Fig. 448. Eachsupport consists of two pieces of pipe, one telescoping within. Fig. 448. the other, and provided with clamps by means of whichthey are adjusted to any desired length. The plank is laiddirectly upon these pipe supports. The air for working thedrills is carried from the air pipe G to the bench by meansof the bench hose //. The manifold K attached to the endof the bench hose contains hose connections for all the ditch L on the opposite side of tunnel from the air pipedrains the tunnel. 954 RAILROAD CONSTRUCTION.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
