The Stub Turnout Template will generate an accurate drawing of a stub turnout in many popular scales and gauges. The various settings below may be modified to fit particular prototypes and model hardware. There are also options to control many layout options, such as the position of the switch-stand.

Scale, Gauge: Ties: Switch-stand Position:
Turnout: Frog Tie: Switch-stand Tie:
Drawing Scale: Tie Spacing: (Proto) Switch-stand Spacing: (Actual)
Units: Tie Size: wid x len (Proto)

N: Frog Number F: Frog Angle (Rad) F = 2 atan(1 / (2 N)) Fd: Frog Angle (Deg) Fd = 180 F / pi
R: Radius Rmax: Maximum Radius Rmax = (Pa + Pb - 1.5 Gl) / (F - tan(F / 2))
Pi: Point of Intersect Pi = R tan(F / 2) Pc: Point of Curve Pc = Pi + Pi cos(F)
G: Track Gauge H: Half Gauge H = G / 2
Pa: Point A Pa = H / tan(F) Pb: Point B Pb = H / sin(F)
Pf: Theor. Pt. of Frog Pf = Pi + Pa + Pb
Pf = 2 R G
Ph: 1/2" Pt. of Frog Ph = N cos(F / 2) / 2 / Scale
Fl: Flangeway Fg: Frog Gap Fg = Ph + 2 Fl / tan(F) Gl: Guard Length Gl = 2 Fl / tan(F)
Pf3: Pt of Frog Wye & 3-Way Pf3 = Pi + Pa
Pf3 = 2 R H - H2
N3: Three Number N3 = 1 / tan(F3)
F3: Three Angle (Rad) F3 = 2 asin(Pf3 / R) F3d: Three Angle (Deg) F3d = 180 F3 / pi
D: Throw Distance S: Stub Length
S = 2 R D + D2
Click on Image to Download
LEGEND: Scale: xx pixels per inch, Grid: 1 inch. TIE COUNT: Notes:
  • Pf or Pf3 in RED indicates that the frog is curved.
  • Rail on ties with an X on them are not spiked (these are the stub rails).
  • The tie layout routine puts a tie right at the last spike point before stub rails begin.
  • The tie layout routine either straddles the frog point with two ties or puts a tie directly under the point.

© Copyright 2016, 2017 by Russell Shilling