Rail creep is defined as the longitudinal movement of rails with respect to sleepers in a railway track. The most serious effect of rail creep is buckling of the track laterally, which can result in derailment if not addressed. There are several causes of rail creep, including wave action as wheels load and unload the rails, percussion from rail joints, dragging forces as trains start and stop, and thermal expansion/contraction from temperature changes. To remedy rail creep, tracks are adjusted through manual means such as grinding rails, replacing worn fastenings, or using mechanical correctors that push rails back into position.

1. Dr. Walied A. Elsaigh
welsaigh@ksu.edu.sa
Asst. Prof. of Civil Engineering
Jumada’-I 1437H
CE 435
Railway Engineering
Creep of Rails

2. Background
Creep of Rails is defined as the longitudinal movement of
rails with respect to sleepers in a track.
In some positions along the railway track, rails moves several
centimeters per month (16 cm/month) while in other location
movement is much less. Use your engineering sense to tell which
direction the rail creeps?! Direction of
motion of locomotive? Think about it!
What is the ultimate consequence of rail creep?
The most serious effect of creep is
buckling of track in lateral direction.
If not properly removed, then
it may result in severe accident
due to derailment.
With reference to previous class discussions, can you now identify all rail
track defects that might result in derailment? Compile a list

3. Creep Signs (Symptoms)
What are the signs/ indication for creep? In other words,
how do you pickup creep when visiting railway tracks

4. Why Creep Takes Place?
There are mainly six causes (mechanisms) behind creep defect:
Wave action.
Percussion action.
Drag action.
Starting, accelerating, slowing, or stopping of a train.
Expansion or contraction of rails due temperature.
Unbalanced traffic.

5. Cont. Why Creep Takes Place?
Wave Action
According to the wave theory, the rail creep is caused due to formation of
the crest curve ABC ahead of the wheels, as the result of deflection under
load. The wheels push the rails in the direction of train movement, causing
creep. The rear crest gets back to its normal position.
The pitch and depth of
wave depends on:
Stiffness of track
Stability of formation.
Track modulus.
Note: More depth and
pitch, the more creep.
Reducing wave action will reduce creep. This can be achieved by
increasing the track stiffness: Use ballast with good interlock (angular in shape).
Larger rail section.
Closer sleeper stiffness.
Train Movement

6. Cont. Why Creep Takes Place?
Percussion Action
Creep occurs due to impact load (R)
of wheels at the rail end at joints.
Horizontal component of the load (P)
pushes rails in the direction of train movement, causing creep. Next
wheel will do the same (cumulative creep effect)
What would be the effect of Q? bend
the rail down. What is the name of
this defect?
This situation is aggravated by: Weak and loose fish bolts.
Worn out fish plate.
Loose packing of joints.
Wide expansion gap.
Heavy axle load moving at high speed.
Can you now compile a
list of all defects caused
by loose packing of joints?

7. Cont. Why Creep Takes Place?
Dragging Theory
Wheels of moving locomotive tends to push rails
backward, while moving railcars pushes rails forward
(due to wave action).
Thus the rails at state of forward/backward movement
as trains move on. The final result is creep at the
direction of train movement.
Locomotive
Drag effect
Rail cars
Wave action effect
Greater than the

8. Pictures adapted from: http://www.studylecturenotes.com/
engineering/transportation-engineering/161-what-is-creep
When train starts its journey,
the wheels pushes the rail
backward [direction of creep is
backward].
When brakes are applied at
the end of the journey, wheels
of the rail cars tend to push the
rail track in forward direction
[direction of creep is forward].
Starting Train
Stopping Train
Train Movement
Train Movement
Direction of Creep
Direction of Creep
Cont. Why Creep Takes Place?
Starting, Accelerating,
Slowing or Stopping train

9. Cont. Why Creep Takes Place?
Expansion or Contraction of Rails
Due to Temperature Change
Increase of
temperature
Rails creep
both sidesDecrease of
temperature
KSA environmental conditions! Class discussion

10. Cont. Why Creep Takes Place?
Unbalanced Track
In a single line system if heavy equal
traffic (load magnitude and repetition)
runs both direction, the creep will be
balanced. BUT if train runs full in one
direction and empty when back, the
creep is unbalanced.
How it works if double track system was the case?
KSA phosphate trains!?
Class discussion

11. Cont. Why Creep Takes Place?
Miscellaneous
Effect of Alignment
Creep is greater on curves compared to straight
lines. Use your engineering sense to tell why?
Effect of Grades
Creep would be higher at steeper gradient. Would this
be one of the reasons why only small gradients are
allowed in railway tracks?
If the train is travelling up hill, then the direction of
creep is ….
If the train is travelling downhill, then the direction of
creep is ….

12. Effects of Creep

13. Cont. Effects of Creep

14. Measures
for Creep

15. Methods for Creep
Correction (Remedy)

16. Cont. Methods for Creep
Correction (Remedy)

17. Cont. Methods for Creep
Correction (Remedy)

18. Thank You