. The railroad and engineering journal . ns necessary, for a transition curve are complied with. with all necessary accuracy, by introducm E, to which A B shall be tangent Platl XL J I/. ng a curve A h Cwhich shall pass are 100 ft. or 200 ft. from C either way, and the offset isalways measured toward the outside of the curve, as^/;and ;/ in. The distances A B and D E have been consid-ered equal. This is. not actually the case, however, A Bbeing nearly equal to C E, and C E a. trifle longer thanD E. The difference, however, is so slight that it may beentirely disregarded. Within the limits laid
. The railroad and engineering journal . ns necessary, for a transition curve are complied with. with all necessary accuracy, by introducm E, to which A B shall be tangent Platl XL J I/. ng a curve A h Cwhich shall pass are 100 ft. or 200 ft. from C either way, and the offset isalways measured toward the outside of the curve, as^/;and ;/ in. The distances A B and D E have been consid-ered equal. This is. not actually the case, however, A Bbeing nearly equal to C E, and C E a. trifle longer thanD E. The difference, however, is so slight that it may beentirely disregarded. Within the limits laid down in thetable, the greatest difference between A B and D E iswhen the circular curve is 16° 30 and the offset D B 20ft., and even in this case it is only 2 ft., which distancewould not in any way affect the practical accuracy of thecurve A g C m E. The manner of running in these curves is as follows :The tangent A Bvs, run up to any point, as B, where, fromthe configuration of the ground, it is deemed advisable tointroduce a through the point C (CD = \ B D) and which shall betangent to the circular curve DEE. The curve A h Cm E is not, of course, a theoreticaltransition curve ; it is of the same radius throughout, and issimply a curve with a radius larger than that of the circularcurve, and connecting the circular curve with the tangent. The accompanying table (which is numbered as PlateXLV) contains all the required data for running in transi-tion curves of the above-mentioned type. In this tablecolumn I contains the degree of curvature of the circularcurve, the chords subtending this angle being 100 ft. long. Column 2 contains the radii of the curves. Columns 3, 5, 7, 9 to 19 contain the distances A B andD E (Plate XLIV) for curves of different radii and offsetsof different lengths. The numbers at the head of the col-umns are one-half D B or C B. Columns 4, 6, 8, 10 to 20 contain the offsets from thechords A g C and C;« j5connecting the points A Cand C E. The po
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Keywords: ., bookcentury1800, bookdecade1880, bookidrailroadengi, bookyear1887
