Correct Answer - Option 4 : All of the above
Concept:
The longitudinal movement of rails along with sleeper (sometimes) is called creep in rails. This happens due to longitudinal horizontal force produced by wave-shaped deflection of rail under rolling dynamic load of wheel and also due to braking force produced by stopping to slow down a train.
The following are some major effects of creep in rails:
1. The most serious effect of creep is the buckling of track in lateral directions. If unattended and not properly removed then it causes derailments which leads to accidents.
2. Sleepers do not remain at fixed position and then gauges of the track get disturbed. The alignment and rail level is also disturbed.
3. The gap between two rail lines are widened at some places while closer at some places causing fishplate bolts to be pulled or broken.
4. The location of points and crossings and interlocking mechanism are also get disturbed.
