Question

The maximum limit of super elevation on B.G. track in India is
1. 76.2 mm
2. 83.2 mm
3. 101.6 mm
4. 165.1 mm

Answer 1

Correct Answer - Option 4 : 165.1 mm

Explanation:

Superelevation:

(i) It is the difference between the height of outer rail and inner rail on curve.

(ii) It is also known as cant.

(iii) Inner rail is taken as the reference rail and w.r.t. inner rail, outer rail is raised.

Formula for superelevation:

\(e = \frac{{G{V^2}}}{{127R}}\)

Where,

G = Gauge

V = Speed (in m/s)

R = Radius (in m)

Maximum value of cant (e_max):

	B.G. Track		M.G.	N.G.
	< 120 kmph	> 120 kmph
emax (actual)	16.5 cm	18.5 cm	10.0 cm	7.6 cm

So, e_max for BG Track is 16.5 cm = 165 mm

Objective of Providing a superelevation:

(i) To neutralize the effect of centrifugal force.

(ii) Achieve equal distribution of wheel loads.

(iii) To improve the comfort level of passengers.

(iv) To avoid jerk when rolling stock moves from a straight section to a curved section.