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GATE 2017 CE (CE2) – Question 21

Transportation Infrastructure · Geometric design of railway track: speed and cant · 1 mark · Multiple choice

For a broad-gauge railway on a horizontal curve of radius R m, the equilibrium cant e for speed V km/h is ______.

  1. $e=1.676V^2/R$
  2. $e=1.315V^2/R$
  3. $e=0.80V^2/R$
  4. $e=0.60V^2/R$

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Correct answer: (B) $e=1.315V^2/R$

Explanation

Balance centrifugal acceleration with track inclination: $e/G=v^2/(gR)$. Using $G=1.676$ m and $v=V/3.6$, convert e to millimetres: $$e=\frac{1000(1.676)V^2}{9.81(3.6)^2R}\approx1.318\frac{V^2}{R}.$$ This matches the conventional rounded coefficient 1.315 (B). The choices implicitly express cant in millimetres.