. The Street railway journal . ad and are magnified fifty diameters. :rtT FIG. 1 FIG. 2 Fig. 2 shows the structure of an 80-lb. rail of somewhat thesame general composition as that above, namely: Per Cent Carbon 396 Phosphorus 072 Manganese 660 Sulphur 033 Silicon 286 This rail was rolled a few years ago and gives a good in-dication of the far greater coarseness of structure of presentpractice. Under the same traffic the one has given long ser-vice while the other would cut out rapidly. Fig. 3 represents about the coarsest structure obtained atpresent practice, 90-lb. section, the composition
. The Street railway journal . ad and are magnified fifty diameters. :rtT FIG. 1 FIG. 2 Fig. 2 shows the structure of an 80-lb. rail of somewhat thesame general composition as that above, namely: Per Cent Carbon 396 Phosphorus 072 Manganese 660 Sulphur 033 Silicon 286 This rail was rolled a few years ago and gives a good in-dication of the far greater coarseness of structure of presentpractice. Under the same traffic the one has given long ser-vice while the other would cut out rapidly. Fig. 3 represents about the coarsest structure obtained atpresent practice, 90-lb. section, the composition being: Per Cent Carbon 620 Phosphorus .094 Manganese Sulphur .033 Silicon 100 Such a rail wears relatively rapidly, tending to brittlenesswhen the steel is unsound. Fig. 4 shows about the average of the better grade of pres-ent practice, 90-lb. rail. Structure of this character is muchtougher and safer than that indicated by Fig. 3. * Abstract of paper presented at the meeting of the New York RailroadClub, Nov. 16, November 24, 1906.] On noting the vast differences which have been shown, thequestion at once arises, why is not the former close-grainedshow wearing structure produced to-day? Is the change duemerely to the insistent efforts of the mills for higher tonnageor do other elements enter into the case. The answer iscomplex. In the first place the increased weight of the pres-ent sections of 90 or 100 lbs. per yard instead of 60 or 65 radically upset the ratio between the various componentsof the area of the rail, that is, head, web and flange. Theformer is far thicker and of much greater mass than formerly,while the other parts in many cases have increased but littlein thickness or even have decreased. As a result of thesechanges the flange gets to the lowest temperature at whichit can be rolled long before the head reaches the same tem-
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
