. Railroad construction. Theory and practice. A textbook for the use of students in colleges and technical schools. By Walter Loring Webb . y80-pound) rails when placed base to base, to say nothing of thef necessary for spikes, it becomes necessary to cut the flangeof the guard-rail. The length of the rail is made from 10 to15 feet, the ends being bent as shown in Fig. 132, so as to 278 RAILROAD CONSTRUCTION. §2t)2. prevent the possibility of the end of the rail being struck by a. wheel-flange. MATHEMATICAL DESIGN OF SWITCHES. In all of the following demonstrations regarding switches,turnouts,
. Railroad construction. Theory and practice. A textbook for the use of students in colleges and technical schools. By Walter Loring Webb . y80-pound) rails when placed base to base, to say nothing of thef necessary for spikes, it becomes necessary to cut the flangeof the guard-rail. The length of the rail is made from 10 to15 feet, the ends being bent as shown in Fig. 132, so as to 278 RAILROAD CONSTRUCTION. §2t)2. prevent the possibility of the end of the rail being struck by a. wheel-flange. MATHEMATICAL DESIGN OF SWITCHES. In all of the following demonstrations regarding switches,turnouts, and crossovers, the lines are assumed to represent thegauge-lines—, the lines of the inside of the head of therails. 262. Design with circular lead-rails. The sim^^lest method is to consider that the lead-rails curveout from the main track-rails by arcsof circles which are tangent to the mainrails and which extend to the frog-jDointF. The simple curve from D to F \^of such radius that (^ -|- ^g) vers 7^= g^in which F = the frog angle, g —gauge, Z = the lead (^F), andr = the radius of tne center of theFig. 137. switch ^ + ig = 9 vers I^ Also BF-^ BD = cotiF, BD = g; BF=Z. (74) Also Z Z QT g cot ^F . (;• + *</) sin F; 2r sin \F. (75)(76)(77) These formulae involve the angle F. As shown in Table III,the angles {F) are always odd quantities, and their trigononietricfunctions are somewhat troublesome to obtain closely withordinary tables. The formulae may be simplified by substitut-ing the frog-number n^ from the relation that n =z \ cot \ \g = L cot F and r -\- ^g = L cosec F^ r § 262. SWITCHES AND CROSSINGS. 279 then r — \L (cot F-\- cosec F) = ^g cot h,Fio^oi FA;- co^^ec 7^) = i^ ^*-^t^ i-^^5 since (cot a -|- cosec ol) = cot ^^-»r = 2^/^^ (78) Also L = 2g?i, (TD) from which r — ?i X ^- (80) These extremely simple relations may obviate altogether thenecessity for tables, since they involve only the frog-nnmber andthe gauge. On account of the gre
Size: 1568px × 1594px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., book, bookcentury1900, bookdecade1900, bookpublishernewyorkjwiley
