. Elements of railroad track and construction . ay be hewed if they give a true surface. Incase of only one block being used, it is sometimes spec- 1 PRACTICAL TURNOUTS. 149 ified that it shall be seveninches thick, fourteen to six-teen inches wide, and twelveto fifteen feet long dependingupon the standards of theparticular railroad. 146. Switch - Timbers.—In order that the ties mayextend the same distance out-side the rails, it is necessarythat the ties for a switch bemade longer than the regula-tion tie. These ties of speciallength are called switch-tim-bers. When the regular tiesare 8^ feet
. Elements of railroad track and construction . ay be hewed if they give a true surface. Incase of only one block being used, it is sometimes spec- 1 PRACTICAL TURNOUTS. 149 ified that it shall be seveninches thick, fourteen to six-teen inches wide, and twelveto fifteen feet long dependingupon the standards of theparticular railroad. 146. Switch - Timbers.—In order that the ties mayextend the same distance out-side the rails, it is necessarythat the ties for a switch bemade longer than the regula-tion tie. These ties of speciallength are called switch-tim-bers. When the regular tiesare 8^ feet long and the gaugeis 4 feet 8 inches, the end ofthe tie is 20f inches from thegauge line. A switch may belaid roughly with ordinaryties by placing a tie under themain track and the next tieunder the turnout track, al-ternately. This gives an un-equal bearing for the differentrails, necessitates an excessiveamount of timber, and is usedonly when proper switch-tim-bers cannot be obtained. A set of switch-timbers fora No. 6 turnout is shown in. 150 RAILROAD TRACK AND CONSTRUCTION. Fig. 88. The lower ends of the timbers follow a curveparallel to the curve of the turnout and 20f inches fromthe gauge of the outer rail, the timbers being cut to thenearest inch in length. Switch-timbers are placed underthe turnout up to the point where the tracks are farenough apart to allow regular ties to be used, as shownto the right of Fig. 88. As soon as this point is reachedthe outer ends of the ties under the turnout are grad-ually placed closer together until the ties are normal, orradial, to the track. On some railroads, instead of having each switchtimber of different length with the center of their endsfollowing the parallel, or concentric curve, two or moreadjacent timbers are made the same length, providedthe variation from the theoretic length is not too method is indicated by the broken lines at the lowerpart of Fig. 88, three timbers being taken of equal length,the middle
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