Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

213 OF ENGINEERING FORMULÆ. Practical Rule fob Determining the Eleva TION OF THE OUTJEB RAIL FOR ANY RADIUS OH FOR ANY COMBINATION OF CURVE WITH Straiqbt. (J. Price, ‘Min. Inst. Civ. Eng.,’ vol. xxxii.) G = Gauge of the railway in feet. C = The length in feet of a chord whose versed sine V will ecpial the required eleva- tion. C jvVg. For 40 miles per hour the length of C = 68-7 feet for 5' 6" gauge, or = 63 • 6 feet for 4' 8|" gauge = approximately a Gunter’s chain of 66 feet. ° Make a chord » C and stretch it on the inner aide of the rails: the distance of th$ rails from it at its middle will equal the proper elevation, no matter what the radius may be.