. Steel rails; their history, properties, strength and manufacture, with notes on the principles of rolling stock and track design . the stresses in the rail, caused bysudden changes in temperature. It will be seen that this frictional resistance may cause an initial tensilestress of about 4000 pounds per square inch in the 100-pound rail at times ofa sudden fall in temperature. * Revue Gcnerale des Chemins de Fer, Paris, 1908, Vol. 31, pp. 8-14. 262 STEEL RAILS The tension set up in rails of lighter section in falling temperatures, beforethey render in the splice bars, is considered by Dr. P.
. Steel rails; their history, properties, strength and manufacture, with notes on the principles of rolling stock and track design . the stresses in the rail, caused bysudden changes in temperature. It will be seen that this frictional resistance may cause an initial tensilestress of about 4000 pounds per square inch in the 100-pound rail at times ofa sudden fall in temperature. * Revue Gcnerale des Chemins de Fer, Paris, 1908, Vol. 31, pp. 8-14. 262 STEEL RAILS The tension set up in rails of lighter section in falling temperatures, beforethey render in the splice bars, is considered by Dr. P. H. Dudley to beimportant and indirectly responsible for a large number of the cracked or brokenrails which occur during falling temperatures. Records and dates of brokenrails taken by Dr. Dudley for a number of years, when compared with thedates of decided falling temperatures, were found to practically coincide, butas soon as the temperature would rise, relieving the rails from tension orputting them in compression, the breakages would cease, except in cases of adevelopment of a check which commenced in a falKng SHEAR Fig. 182. — Shearing Stress in 100-pound A. S. C. E. Rail and Splice Bar. Total Shear, 24,000 Pounds. If we consider the effect of the frictional resistance between the splice barand the rail, it is apparent that the bar shown in Fig. 182 will act as anintegral part of the rail until the longitudinal shear at the surfaces of contactof the rail and the bar exceeds the resistance caused by friction on thesesurfaces. This resistance for a 20-inch splice bar may be taken as 4000pounds per linear inch for the entire joint, or 1400 pounds per square inch for STRESSES IN THE RAIL 263 the upper surface of contact, and 500 pounds per square inch for the lowersurface of contact. It is seen from the figure that the surface friction is sufficient to carry atotal shear at the section of 24,000 pounds, and by referring to the rail diagramsgiven in Figs. 171 an
Size: 1509px × 1655px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidsteelrailsth, bookyear1913
