04 Rail Sleepers (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
Rail Sleepers

2. Textbook
Railway Engineering,
Satish and Agarwal,
2nd edition, 2013
Chapter 7
Page 112-140

3. Background
Sleepers are members generally laid transverse to the
rails on which the rails are supported and fixed.
The main purpose/ Function of the sleepers is to cushion and
transmit the load of the train to the ballast section as well as to
maintain gauge.
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4. Sleeper Requirements

5. Classification of Sleepers
 Timber or wooden sleepers {hardwood, softwood}.
 Metal sleepers {cast iron or steel}.
 Concrete Sleepers {Reinforced, Prestressed}.

6. Wooden
Sleepers
Pressure treated by a preservative
Their life depend on ability to resist:
Wear
Decay and attack by fungal and insects
Quality of timber {softwood, hardwood}
Long life of 10-12 years depending upon
the climate, condition, nature of traffic,
wood quality etc.
Much useful for heavy loads and high speeds.
Good insulators and hence good for track circuited railway tracks.
They are able to accommodate any gauge.
Suitable for salty regions and coastal areas.
Can be used with any section of rail.
They are not badly damaged in case of derailment.
They are not corroded.
Cheaper than any other types of sleepers [location!]

7. Steel Sleepers
Steel ties are often refer to locations or
areas not favourable to the use of either
timber or concrete, such as tunnels with
limited headway clearance. They have
also been utilized in heavy curvature
prone to gauge widening.

8. Cont. Steel Sleepers
Longer life, 20-25 years, than wood.
Free from decay and are not attacked by fungal.
Connection between rail and sleeper is stronger.
Connection between rail and sleeper is simple.
Having better lateral rigidity. (creep resistance)
Good scrap value.
Liable to corrosion by moisture and should not because in salty regions.
Good conductor and hence cannot be used in track circuited regions.
Cannot be used for all sections of rails and gauges.
Very costly.
Can badly damaged under derailments.
The rail seat is weaker.
Good shock absorber as there is not cushion between rail foot and ballast.
Advantages
Disadvantages

9. Concrete
Sleepers
Concrete sleepers are rapidly gaining acceptance for heavy
haul mainline use, (both track and turnouts), as well as for
curvature greater than 2°.
Manufactured of pre-stressed
concrete containing reinforcing
steel wires.
Concrete sleepers weigh
approx. three times a timber
sleeper. {heavier than timber}
Pad to absorb,
cushion & tighten
sleepers to rail.
Utilized in KSA
Twin concrete blocks-steel bar sleepers

10. Cont. Concrete Sleepers
Durable with life of 40-50 years (wooden sleeper 15-20 years!!).
Can be produced on large quantities locally by installing a plant.
Heavier than other types, giving better lateral stability to the track.
Good insulators and thus suitable for use in track circuited lines.
Efficient in controlling creep - They are not attacked by corrosion.
Free from attacks of vermin and decay.
 suitable for all types of soils.
 Most suitable for welded tracks- Prevent buckling more efficiently.
 Initial cost is high but proves to be economical in long run.
 Effectively and strongly hold the track to gauge.
 Inflammable and fire resistant.
Difficult to be handled (heavy).
Difficult to be manufactured in different sizes (not suitable
for bridges and crossing).
 Can be damaged easily while loading and unloading.
Advantages

11. Cont. Concrete Sleepers
KSA Practice Production Process
Production of the main-track sleepers is according to the so-called
carousel process, in the production plant in Hail constructed
especially for North-South Line. In this process, high-strength
concrete is filled into mobile forms, and then stored for curing in
insulated chambers under exactly controlled climatic conditions.

12. Cont. Concrete Sleepers
KSA Practice
http://www.railone.com/en/main-nav/products/freight-and-heavy-haul-rail-transport/saudi-arabia.htmlAdapted from:

14. ?
Sleeper Density / Spacing
What are the factors that affect sleeper spacing?
Do we need to have spacing between sleepers? Yeh,
Some spacing between sleepers is required to allow packing
of ballast!
Try it when you have time:!
If you know that the width of
sleeper is 265 mm (earlier table),
what is the edge-to-edge spacing
of these sleepers?
What is the sleeper spacing used in KSA ?
at 1800/km spacing.