Question

The transition length based on permissible speed for a 2° curve with maximum speed of 100 kmph on a BG railway track will be _______ m. [Consider, G = 1.676 m]

• A. 112.06

Answer 1

The correct option is A 112.06
Radius of curve $=\frac{1720}{2}=860m$

Super elevation, $e=\frac{G{V}^2}{1.27R}$

$=\frac{1.676\times {\left(100\right)}^2}{1.27\times 860}=15.35cm$

The maximum permissible cant on BG is 16.5 cm and permissible cant deficiency (CD) is 7.6 cm.

$\therefore$ Length of transition curve is :

(i) L = 7.2e = 7.2 × 15.35 = 110.52 m

(ii) L = 0.072e $V_{max}$ = 0.072 × 15.35 × 100 = 112.055 m

(iii) L = 0.073 × (CD)$V_{max}$ = 0.073 × 7.6 × 100 = 55.48 m

$\therefore$ L is max of { (i), (ii), (iii) }

$=112.055m\simeq 112.06m$