Test: Maintenance, Curvature of Track & Creep - 2 - Civil Engineering (CE) MCQ

For BG track grade compensation is 0.04% per degree of curve. For 4° curve grade compensation will be
= 4 x 0.04 = 0.16 % .

Grade compensation = 0.04 x 3 = 0.12%
Permissible gradient = 

Curve resistance =  = 0.08 tonne

Preliminary survey is called initial location survey. Detailed survey is called final location survey.

Wave theory states that wave motion is set up by moving of wheels. A vertical reverse curve is formed in the rails ahead of the wheels, resulting from the rail deflection under the load, is the chief cause of creep.
Percussion theory states that the creep is due to impact of wheels at the rail end a head at joints. Though the creep is very small in single impact but cumulative effect of number of wheels in quick succession results in sufficient creep.
Drag theory states that backward thrust on driving wheels of the locomotive of train has got a tendency to push the sail off the track backward while the other wheels of the locomotive and the vehicles push the rail in the direction of travel. This results in creep of rails in the direction of movement of trains

Track modulus is a measure of stiffness of the track and is defined as load per unit length of the rail, required to produce a unit depression in the track.

The track modulus depends upon the gauge, the type of rails, the type and density of sleepers, the type of section of ballast and sub-grade.

Hauling capacity = μ x W x n
= 0.166 x 24 x 4 = 15.936 
= 16 tonnes

The maximum permissible speed on the railway track is limited by the speed on the curve:
(i) Maximum sanctioned speed.
(ii) Safe speed over the curve by martin’s formula depends upon gauge type and radius or degree of curve.
(iii) Transitive curve whether present or not.
(iv) Maximum allowable superelevation.