05 Rails (Railway Engineering Lectures هندسة السكك الحديدية & Dr. Walied A. Elsaigh)

1. Dr. Walied A. Elsaigh
welsaigh@ksu.edu.sa
Asst. Prof. of Civil Engineering
Jumada’-I 1437H
CE 435
Railway Engineering
RailsFoot
Web
Head
Flat Foot Rail

2. Text Book
Railway Engineering,
Satish and Agarwal,
2nd edition, 2013
Chapter 6
Page 81-105

3. Functions of Rails

4. Types of Rails

5. Standard Rail Sections
Branding and Stamping
Common section codes
RE: American Railway Engineering Maintenance of Way Association (AREMA).
REHF: AREMA “head free” section.
ARA-A: American Railway Association, “A” section.
ARA-B: American Railway Association, “B” section.
ASCE: American Society of Civil Engineers.

6. Cont. Standard Rail Sections

7. HT = Height
BW = Width of Head
HW = Width of Head
W = Web (at center point)
HD = Depth of Head
FD = Fishing
BD =Depth of Base
E =Bolt Hole Elevation
X-Section of Rail
Cont. Standard Rail Sections

8. Cont. Standard Rail Sections
The rail is designated by its weight per unit length.
52 kg/m rail denotes that it has a
weight of 52 kg per metre length

9. Factors affecting choice of appropriate rail section:
Heaviest axle load
Maximum permissible speed
Depth of ballast cushion
Type and spacing of sleepers
Selection of Rail Section
Rule of Thumb (Relationship between
maximum axle load and weight of rail section)
Maximum axle load = 560 × sectional weight of rail
Example #1: Determine the maximum axle load for 90 lb/yard rail section
Maximum axle load = 560 × 90 lbs = 50,400 lbs or 22.5 t
Example #2: Determine the suitable rail section weight (kg/ m) to carry a
maximum axle load of 29 ton? (ans: 52kg/m)
Sectional weight of rail in lbs per yard or kg per metre

10. Lack of facilities for transport of longer rails, particularly on curves.
Difficulties in manufacturing very long rails.
Difficulties in acquiring bigger expansion joints for long rails.
Heavy internal thermal stresses in long rails.
Rail Length
Theoretically, the longer rails are preferred, why?
Reduces number of joints less cost (construction & maintenance)
Provides smooth and comfortable rides.
Length of a rail is limited, Why?
Find out the following: Rail section and length used in KSA

11. Rail Tests Falling Weight Test
[Tup Test]
A rail piece of 1.5 m (5 ft) is cut. The rail is supported between the bearers
at a prescribed distance. A tup of specified weight (see table) is dropped
from a height of 7.2 m on the centre of the test piece.
One falling weight test is done for
every cast of 100 metric tonnes.
The rail specimen should withstand
the blow without any fracture.

12. Rail Tests
Tensile Test
A test piece is taken from the head of a rail section and subjected to
the tensile test.
The tensile strength of the rail should not be less than 720 N/mm2,
minimum elongation of 12%

13. Rail Tests
Hammer Test
No fracture should occur or a lap be disclosed,
otherwise the batch is rejected.
The foot of the test rail piece is rigidly gripped in a vertical position
and the head of the rail is struck with a 4.5 kg hammer. Sufficient number
of blows are given till the web bends and the dimensional value of A given
in the Table below

14. Rail Defects
Rail Wear
Due to the passage of moving loads and friction between the rail
and the wheel, the rail head gets worn out in the course of service.
The impact of moving loads,
Forces due to acceleration, deceleration, and braking of wheels,
The abrasion due to rail–wheel interaction,
 Effects of weather conditions (i.e. temperature, rains, presence of sand).
Why wear occurs ? (causes of rail-head wear)

15. Rail Defects
Types of
Rail Wear
Where in the rail wear occurs ?
on top of the rail head (vertical wear)
on the sides of the rail head (lateral wear)
on the ends of the rail (battering of rail ends)

16. Rail Defects Locations
of Rail Wear
Where in the track wear occurs ?
on sharp curves, due to centrifugal forces
on steep gradients, due to the extra force applied by the engine
on approaches to railway stations, due to acceleration and deceleration
in tunnels and coastal areas, due to humidity and weather effects

17. Rail Defects
How to Reduce Rail Wear ?
Better maintenance of the track to ensure good packing
as well as proper alignment and use of the correct gauge
Reduction in the number of joints by welding
Lubricating the gauge face of the outer rail in case of curves
Providing check rails in the case of sharp curves

18. Rail Defects
 By weighing the rail
 By profiling the rail section (Special instruments are available)
incorporates the latest laser and video camera technology to provide accurate and
immediate report on the profile and wear condition of the rail whilst travelling at
track speeds. The video cameras capture full cross-sectional rail profiles from the
base/web fillet area up to the top-of-rail surface to allow comprehensive and
accurate rail measurements.
http://www.mermecgroup.com/diagnostics/tr
ackin%20specti-on/60/1/rail-profile.php
Adapted from:
How to Measure
Rail Wear ?

19. Rail Defects Rail End Batter
The hammering action of moving loads on rail
joints batters the rail ends in due course of time.
Batter = Beat (hit)
How measured?
If the batter is up to 2 mm, it is classified ‘average’,
If it is between 2 and 3 mm, it is classified as ‘severe’.

20. Rail Defects Rail End Batter
Adapted from: http://www.bitlanders.com/blogs/corrugation-wear-of-rails-
failure-of-rails-and-rails-welding/441935

21. Rail Defects Hogging Rail
Rail ends get hogged due to poor maintenance of the
rail joint, yielding formation, loose and faulty fastenings.
Remedial action? (1) Replace joint, (2) Welding joint,
(3) Dehogging, (4) Cropping
Hogged rails: Due to worn out of
rail ends due to load repetition,
the rail gets bent down at its
ends, creating what is termed as
“hogged rails”.
Consequence ? Rough riding, more vibration leading to more defects.
Causes? loose packing under joints and loose fish plate.

22. Rail Defects Corrugated Rail
Corrugated or Roaring rails: The heads of rails corrugate (fine
depressions on the surface of rails). Causes roaring sounds when
wheels pass over it.
Causes? Found at places where trains brakes or starts its journey, other
reasons such as: composition of steel used to manufacture rails.
Consequences? (1) Unpleasant roaring sound which cause discomfort
to passengers and residents along side the rail track
(2) Vibration causes further deterioration to other track
elements.
Remedial action? (1) Replace rail if corrugation is severe and the defect is
limited to small number of rails
(2) Grind top surface of rail, a grinding train moving at
3 km per hour can be used (as in Germany).