Figure 6-28. Turnout Design

Eq 6-12

S = Switch angle (degrees).

h = heel spread (inches). (Standard dimension is 6.25 in.).

t = thickness of switch point (inches). (Standard dimension is 0.25 in.).

a = length of switch point (inches).

1

Eq 6-13

(*F *+ *S *)

sin

2

C = Long chord (feet).

q = g - e - h (feet), where g is track gage, e is frog toe spread from AREMA Plan 910, Column 21, and h is

the switch heel spread distance (which has a standard value of 0.52 ft).

F = Frog angle (degrees), from AREMA Plan 910, Column 17 (converted to degrees).

S = Switch angle (degrees).

Eq 6-14

R = Radius of curved closure rail (feet).

C = Long chord (feet).

F = Frog Angle (degrees).

S = Switch Angle (degrees).

6-46

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