Lecture 8 Final
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Transcript of Lecture 8 Final
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CE-363
Lecture 8: Wears and Failures in
Rails
Dr. Ankit Gupta, Assistant Professor
Department of Civil Engineering
National Institute of Technology Hamirpur
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Lecture Outline
Wear in rails
Classification of wear
Effects of rail wear
Permissible limits
Remedial measures
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Rails – Wear
Definition
This is one of the prominent defects of
the rails
The surface of the rail, either on the top
of rail head or side of rail head or at the
end of the rail head, gets removed
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Rails – Wear
Major Reasons
Abnormally heavy loads
Fast train speeds
Concentrated stresses exceeding elastic
limit
Gap at joints
Slipping, skidding or striking of wheel
flanges on curves
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Rails – Wear: Classification
On the basis of location
On the basis of position of wear
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Rails – Wear: Classification
Based on location
On sharp curves – due to centrifugal
force
On steep gradients – due to extra effort
On approaches to stations – due to
braking or acceleration
In tunnels and coastal areas – due to
humidity and weather effect
On weak foundations – due to heavy
loads
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Rails – Wear: Based on Position
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Rails – Wear: Type
Based on Position – Top of rail head
Flow of metal
Recurring impact of heavy axle load
Abrasive / corrosive condition
Skidding / burning of head
Improper super elevation / centrifugal
force
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Rails – Wear: Type
Based on Position – Top of rail head
Slipping of wheels on curves
Fluctuation in track
Adzing of sleepers
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Engine Burns
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Flow of Metal
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Rails – Wear: Type
Based on Position – Side of rail head
Rigidity of wheel base
Slipping /skidding of wheels on curves
Greater thrust on inner rail (speed lesser than equilibrium speed)
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Rail Head Side Wear
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Flaking
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Shelling
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Rails – Wear: Type
Based on Position – End of rail head
Loose fish plate, fish bolts
Heavy loads at high speed
Wide joint opening
Difference in rail height at joint
Bad condition of vehicle springs
Poor maintenance of track
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Rails – Wear
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Rail Failures
Category Description of Fracture
A Cracks in the head of the rail
B Solitary cracks in the web or flange of the rail
C Transverse (parallel to rail cross- section) cracks
D Horizontal cracks in the web
E Pieces of head, web and flange broken off at the rail end
F Portion of rail broken off
G Breaks through sections of rail
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Rail Failures
Category Description of Fracture
H Cracks and breaks through welds
J Portions absent from railhead
K Piece of rail broken away though web and head/flange
U
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Category A
Vertical crack through
crown at rail head end
Vertical crack on
running face of rail
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Category A
Horizontal crack on side
of head of rail at end
Horizontal crack on
side of rail head
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Category B
Crack at junction of head
and web
Crack in body of web
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Category B
Crack at junction of
flange and web
Crack in flange
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Category C
Transverse Crack at rail
head
Transverse Crack at
bond
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Category C
Transverse Crack
at bond
Transverse
Crack at flange
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Category C
Vertical Crack at
end
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Category D
Crack in web at end Crack in web along
holes
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Category E
Broken Rail
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Category F
Broken Rail
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Category G
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Horizontal Split Head
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Split Web
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Transverse Defects
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Vertical Split Head
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Head / Web Separation
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Crushed Head
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Bolt Hole Crack
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Rails – Wear: Permissible Limits
Depends up on weight of rail (or weight of
axle)
Limited to 5% of rail weight
Wear of 25% of the section of head is also
allowable
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Rails – Wear: Prevention
Better maintenance of track
Reducing number of joints
Use of heavier and higher UTS rail sections
Use of bearing plates (adzing of sleepers)
Lubricating gauge face
Using check rails on sharp curves
Track renewal
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Rails – Wear: Prevention
Interchanging inner and outer rails
Using special alloy steel
Regular maintenance of rail joints
Welding or dehogging of battered ends
Maintenance of correct gauge
Application of heavy mineral oil in case of
corrosion of rail metal under adverse
atmospheric conditions