What is Creep in Rail in Railway Engg?
What is Rail Creep?
Creep in rail is defined as the longitudinal
movement of the rails in the track in the direction of motion of locomotives.
Creep is common to all railways and its value varies from almost nothing to
about 6 inches or 16cm.
Causes of Creep:-
The causes of rail creep can be broadly
classified into two categories
1.
Major Causes o
Creep
2.
Minor Causes of
Creep
Major
Causes of Creep:-
Major causes of creep also known as principal
causes of creep. Follows are the major causes of creep in rail 1. Creep may be developed due to forces that come into operation when the train is starting or stopping by application of brakes. Increase of starting the wheels pushes the rail backward and hence the direction of creep is in backward direction.
When brakes are applied then the wheels of the vehicles push the rails in forward direction and hence the creep is in forward direction.
2. Creep is also developed due to wave motions. When the wheels of the vehicles strikes the crests, creep is developed.
. Another reason creep develops because of unequal expansion and contraction owing to change in temperature.
Minor
Causes Creep:-
Some of the minor causes of creep in rail are
below:
1.
Rails not
properly fixed to sleepers
2.
Bad drainage of
ballast
3.
Bad quality of
sleepers used
4.
Improper
consolidation of formation bed
5.
Gauge fixed too
tight or too slack
6.
Rails fixed too
tight to carry the traffic
7.
Incorrect
adjustment of super elevation on outer rails at curves
8.
Incorrect
allowance for rails expansion
9.
Rail joints
maintained in bad condition
Magnitude and Direction of Creep:-
Creep is not constant over a given period, it
is not continue in one direction or at uniform rate. Both the rails of the
track may creep in same direction, perhaps both the rails reverse the direction
of creep or one rail creep in opposite direction to that of other.
Results and Consequences of Creep:-
Following are some of the undesirable
consequences of creep 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.
Correction of Creep|Methods against
Creep:-
There are two methods used for the correction
of creep. These are
1.
Pulling back
Method
2.
Use of Creep
Anchors / Anti Creepers
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