248 



turnout must be computed, 

 be found by the formula 



TRACKWORK 



The angle M, Fig. 6, must first 



Then, the lead must be determined by the formula 



Finally, r is given by the formula 

 R + h 



sinM 

 sin (F M) 



When r has been found, the degree of curve is given by the 

 5,730 



formula 



If the main-track curve is not very sharp, this value of d 

 may be obtained by subtracting the degree of curve of the 

 main track from that obtained from the sixth column of 

 the table for stub switches. The lead L may also be taken 



from the table. 



If the curvature of 

 the main track is very 

 sharp, or if the frog 

 angle is very small, the 

 turnout may curve in 

 the same direction as 

 the main track ; in which 

 case, the degree of curve 

 taken from the stub- 

 switch table will be less 

 than the degree of curve 

 of the main track. The 



FIG. 



difference between the 

 two degrees of curve 

 will still be equal to the degree of curve of the turnout. 



If the degrees of curve are equal, the turnout rails will be 

 straight. 



Turnout to the Inner Side of Curved Track. A turnout to 

 the inner side of a curved track is shown in Fig. 7. The radius 

 OR of the turnout is always less than the radius DH of 



