. Railroad construction, theory and practice; a text-book for the use of students in colleges and technical schools . eL STANDARD I-BRIDGES-14-FT. SPAN. NORFOLK AND WESTERN .(1891.). (io jace pays 264.) CHAPTER VII. BALLAST. 231. Purpose and requirements. ^ The object of the ballastis to transfer the applied load over a large surface; to hold thetimber work in place horizontally; to carry off the rain-waterfrom the superstructure and to prevent freezing up in winter;to afford means of keeping the ties truly up to the grade line;and to give elasticity to the roadbed.* This extremely con-de
. Railroad construction, theory and practice; a text-book for the use of students in colleges and technical schools . eL STANDARD I-BRIDGES-14-FT. SPAN. NORFOLK AND WESTERN .(1891.). (io jace pays 264.) CHAPTER VII. BALLAST. 231. Purpose and requirements. ^ The object of the ballastis to transfer the applied load over a large surface; to hold thetimber work in place horizontally; to carry off the rain-waterfrom the superstructure and to prevent freezing up in winter;to afford means of keeping the ties truly up to the grade line;and to give elasticity to the roadbed.* This extremely con-densed statement is a description of an ideally perfect value of any given kind of ballast is proportional to theextent to which it fulfills these requirements. The ideallyperfect ballast is not necessarily the most economical ballastfor all roads. Light traffic generally justifies something cheaper,but a very common error is to use a very cheap ballast when asmall additional expenditure would procure a much betterballast, which would be much more economical in the long run. 232. Materials. The materials most commonly employed aregravel and broken stone. In many sections
Size: 1578px × 1583px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidrailr, bookpublisheretcetc
