Question

According to the wave action theory for creep of rails, the pitch and depth of wave depend upon:

1) Section of rails

2) Track modulus

3) Stiffness of track

4) Stability of foundation

5) Weight of the train

Which of these are correct?
1. 1 and 2 only
2. 1, 2 and 3
3. 2, 3 and 4
4. 3, 4 and 5

Answer 1

Correct Answer - Option 3 : 2, 3 and 4

Concept:

Wave motion is set up by moving loads of wheels. The 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.

The wheels push the wave with a tendency to force the rail in the direction to traffic. On a particular rail, the joint action by several wheels causes creep.

As the wheels move, the lift in front of the moving load is thus carried forward by the wheels and causes creep, whereas the lift at the rear of the wheel gets back to its normal position.

The pitch and depth of wave depend upon the following:

(i) Track modulus

(ii) Stiffness of track

(iii) Stability of formation

The wave action can be reduced (i.e. creep is reduced) by adopting following measures:

(i) Angular and heavy ballast-which develops good interlock,

(ii) Increased stiffness of track,

(iii) Lesser sleeper spacing,

(iv) Bigger section of the rail.