Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

210 Molesworth’s pocket-book Points axd Crossings. CURVE RUNNING FROM STRAIGHT LINK R = Radius of curve. (4 = Gauge of railway. a° = Angle of crossing. x = R - G. L = Length from tangent point of curve to the centre of the crossing = V (R + *))5. Sin. a° = — . . R Rs=______<L_____ Versin. a° Lead of crossing = cotan. a°. In flat curves the width required for the clearance of the flange of the wheel, and for the width of the rail at the heel of the switch, render it necessary to make some allowance in the theoretical length L.